TW201248270A - Light guide plate, planar lighting device and method of producing the light guide plate - Google Patents

Light guide plate, planar lighting device and method of producing the light guide plate Download PDF

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Publication number
TW201248270A
TW201248270A TW101117668A TW101117668A TW201248270A TW 201248270 A TW201248270 A TW 201248270A TW 101117668 A TW101117668 A TW 101117668A TW 101117668 A TW101117668 A TW 101117668A TW 201248270 A TW201248270 A TW 201248270A
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Taiwan
Prior art keywords
light
guide plate
light guide
light incident
incident surface
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TW101117668A
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Chinese (zh)
Inventor
Osamu Iwasaki
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Fujifilm Corp
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Publication of TW201248270A publication Critical patent/TW201248270A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/004—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles
    • G02B6/0041—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles provided in the bulk of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49995—Shaping one-piece blank by removing material

Abstract

The purpose of the invention is providing a light guide plate which has high light utilization efficiency, emits light with less unevenness in brightness, and obtains a center-high distribution (normal distribution). The light guide plate of the invention has more than two layers whose thicknesses change respectively along a direction substantially vertical to the light-emitting surface. The concentration of synthetic particles varies between a first local maximum value on the side of the light incident surface and a second local maximum value greater than the first local maximum value. The light-incident surface is a rough surface which is a cut and polished surface having predetermined periodic structures formed along a direction parallel to the length direction.

Description

201248270. HZ-Ulipil 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種用於液晶顯示裝置等的導光板、 面狀照明裝置（planar lighting device )以及該導光板的製 造方法。 【先前技術】 液晶顯示裝置中’使用自液晶顯示面板的背面側照射 光來對液晶顯示面板進行照明的面狀照明裝置（背光單 . 元）。背光單元是使用導光板、稜鏡片或擴散片等零件來構 ‘ 成，上述導光板使照明用的光源所發出的光擴散來照射液 晶顯示面板，上述稜鏡片或擴散片使自導光板射出的光均 勻化。 目前，大型的液晶電視機的背光單元的主流是將導光 板配置於照明用的光源的正上方的所謂直下型的方式。該 方式中，將多根作為光源的冷陰極管配置於液晶顯示面板 的月面，並將内部设為白色的反射面來確保均勻的光量分 布與必要的亮度。 ' ‘然而’於直下型的背光單元中，為了使光量分布變得 均勻’需要相對於液晶顯不面板垂直的方向的厚度為3〇 mm左右，而難以進一步薄型化。 相對於此’作為可薄型化的背光單元有使用如下的 導光板的邊緣發光（edge lighted)型的背光單元，該導光 板將自照明用的光源射出，且將射入的二規S 向，且使光自與所射入面不同的面即光射出面射出。 201248270[Technical Field] The present invention relates to a light guide plate for a liquid crystal display device or the like, a planar lighting device, and a method of manufacturing the light guide plate. [Prior Art] In a liquid crystal display device, a planar illumination device (backlight unit) that illuminates a liquid crystal display panel from the back side of the liquid crystal display panel is used. The backlight unit is formed by using a light guide plate, a cymbal sheet or a diffusion sheet, and the light guide plate diffuses light emitted from the light source for illumination to illuminate the liquid crystal display panel, and the cymbal sheet or the diffusion sheet emits the light from the light guide plate. Light is homogenized. At present, the mainstream of the backlight unit of a large-sized liquid crystal television is a so-called direct type in which the light guide plate is disposed directly above the light source for illumination. In this embodiment, a plurality of cold cathode tubes as light sources are disposed on the moon surface of the liquid crystal display panel, and the inside is set as a white reflecting surface to ensure uniform light amount distribution and necessary brightness. In the backlight unit of the direct type, in order to make the light amount distribution uniform, it is necessary to have a thickness of about 3 mm in the direction perpendicular to the liquid crystal display panel, and it is difficult to further reduce the thickness. In contrast, the backlight unit that can be made thinner has an edge light-emitting type backlight unit that uses a light guide plate that emits a light source for illumination and that enters the two-gauge S direction. Further, the light is emitted from a surface which is different from the incident surface, that is, the light exit surface. 201248270

«知 V A A 二I 邊緣發光型的背光單元中，提出有使用將用以 使光散射的散雜子狀至翻翻旨中而成的板狀的導光 板0 例如，於專利文獻1中記載有— 性兀瑕别·等元无源繫 置’其侃在於：其包括具杜少丨㈣射人面區域及至 少1個光導出面區域的光散射導光體、以及用以自上述光 射入面區域進行光射人的光源機構，且上述光散射導光體 包含具有隨著遠離上述光射人面而減少厚度的傾向的區 域0 ，另外’於專利文獻2中記載有一種面光源裝置，其特 徵在於·於至少1個非散射導光區域、及使折射率不同的 _子均勻地分散在與其相同的材料巾而賴至少1個散射 導光區域，有重疊部分的板狀體中，將光源燈安裝於端 面，並且藉由兩區域的板厚來局部地調整粒子的濃度藉 此控制來自主面的射出量的分布狀g;且散射導光區域為 凸狀的導絲區塊，非散料光區域為與凸狀的導光體區 塊相對應的凹狀的導光體區塊。 此處，於此種邊緣發光型的背光單元中，因光源所射 出的光並不均勻等原因，而導致自光射出面的人光部附近 射出的照明光產生亮度不均。 々具體而言，作為面狀照明裴置的光源，可使用冷陰極 管或發光二極體（以下，亦稱為「LED (Light EmittingIn the case of the backlight unit of the VAA-I-edge-light-emitting type, a plate-shaped light guide plate 0 using a scattering type for scattering light is proposed. For example, Patent Document 1 discloses that - 兀瑕 · 等 等 等 等 等 等 ' ' ' ' 等 等 等 ' ' ' 等 等 等 等 等 等 等 等 等 等 等 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜 杜The surface area is a light source unit that emits light, and the light-scattering light guide includes a region 0 having a tendency to decrease in thickness as it moves away from the light-emitting surface, and Patent Document 2 describes a surface light source device. The present invention is characterized in that at least one non-scattering light guiding region and a y-sub-particle having a different refractive index are uniformly dispersed in a plate-like body having at least one scattering light guiding region and overlapping portions in a material sheet having the same refractive index The light source lamp is mounted on the end surface, and the concentration of the particles is locally adjusted by the thickness of the two regions to thereby control the distribution g of the emission amount from the main surface; and the scattered light guiding region is a convex guide wire block. Non-bulk light region is convex The guide region corresponding to the concave block light guide blocks light. Here, in such an edge-emitting type backlight unit, unevenness in brightness is caused by illumination light emitted from the vicinity of the human light portion of the light exiting surface due to unevenness of light emitted from the light source. Specifically, as a light source for a planar illumination device, a cold cathode tube or a light emitting diode can be used (hereinafter, also referred to as "LED (Light Emitting)"

Diode)」）。冷陰極管因於兩端形成有電極，故自冷陰極管 的兩端不射出光，而無法射出均勻的光。另外，當使LED 6 201248270 42Ullpif 與導光板的端面相向而配置成陣列狀，並將其用作光源 時，鄰接的LED間具有間隙，發出光的發光面未相連，因 此作為光源，無法射出均勻的光。 即便於如上述般光源所射出的光並不均勻的情況下， 自導光板的端面射人的光亦於導光油擴散，另外，藉由 棱鏡片或擴散片等來擴散，而在某種程度上作為均勻的照 明光自背光單7G射it}，但於導光板的人光部附近，所射入 的^於未充分地擴散的狀態下自光射出面射出，因此自背 光單元射出的照明光會產生亮度不均。 因此，為了抑制導光板的入光部的亮度不均，提出有 藉由將導光板的端面形狀設為粗面或稜鏡、雙凸透鏡等構 造來使光擴散的方式的背光單元。 例如’於專利文獻3中記載有一種側光（side light) 型面光源裝置，其使自以厚度隨著遠離端面而變薄的方式 形成的板狀構件的端面射入的照明光偏向，然後自板狀構 件的一面射出，且設為越是端面的兩端部，自端面射入的 射入光越散射。 另外，於專利文獻4中記載有一種侧光型面光源裝 置’其於射入面上反覆形成具有大致垂直於射出面的1對 斜面的突起，且以於光源的發光區域中，面向光源的中心 侧的斜面變大，於遠離發光區域的區域中，面向光源的中 心側的斜面變小的方式將該些突起形成為不同形狀，於專 利文獻5中記載有一種側光型面光源裝置，其於板狀構件 的射入面上，沿射入面的長邊方向反覆形成由i對斜面所 201248270 ipif 構成的突起。 〇·〇_〜0.30 μηι w圍内以鼻術平均粗糙度^為 面。 ^圍内’將照明光的射人面形成為粗 射入專利文獻7中記载有—種導光板，其在盘光 射入面的長邊方向平杆的 八牡興九 有具有規定的週期構造的切刺研磨=面形成為形成 [先前技術文獻] [專利文獻] 丨，文獻1]曰本專利特開平7_36〇37號公報 [專利文獻2]日本專利特開平11345512號公 [專利文獻3]日本專利特開平㈣，6號公報 [專利文獻4]曰本專利特開^伽如號 [專利文獻5]日本專利特開平似逃7號 [專利文獻6]日本專利特開平Μ·%號公報 [專利文獻η日本專利特開__182478號公報 但是’於使用厚度隨著遠離光源而變薄的 聯方式等㈣料元中，_可實現_的背光單元= 存在光效率ϋ冷陰極管與反㈣的相 比直下型差的問題。 ^ ^ 另外，專利文獻2中所記載的導光板藉由將散射導光 區域的形狀設為凸型’而在某種程度上可 變得均勻，但未考慮為了使射出光量最佳化而調= 8 201248270 4201lpif 光區域的形狀。 另外，若將背光單兀加以薄型、大型化，則為了將光 引導至導光板的内部為止，必須降低散射粒子的粒子濃 度’但若散·子的粒顿度低，朗射人的光於光射入 面附近未充分地擴散，因此有可能於自光射人面附近射出 的射出光中看到因光源的配置間隔等而引起的明線（暗 線、不均）。 另一方面，若於光射入面附近的區域中散射粒子的粒 子濃度咼，則存在如下的疑慮：自光射入面射入的光於光 射入面附近的區域被反射，並作為回光自光射入面射出， 或者被框體覆蓋而無法利用的來自光射入面附近的區域的 射出光增加。 此處’當將導光板加以大型化時，為了自光射出面射 出均勻的光’考慮增加LED等的光源數。但是，對於液晶 電視機等液晶顯不裝置，要求消耗電力的削減、或零件數 的減少等，伴隨大型化的光源數的增加違反該要求。 為了滿足此種要求，如上所述，於先前的導光板中， 進行了於光射入面上形成粗面或棱鏡等的研究。 但是，該些方法談不上已充分地滿足特別是對於大型 化或薄型輕量化的要求。 例如，於在導光板的光射入面上形成粗面的方法中， 因於入光部附近變得容易射出，故在大型的導光板中難以 將光引導至内部為止，而無法自光射出面射出均勻的光。 另一方面，於在導光板的光射入面上形成棱鏡或雙凸透鏡 201248270 πζυ upif 的方法中’存在如下的問題：隨著使導光板變薄，光源與 導光板的光射人面之間的距離相對地變遠，光的射入效率 下降。另外，考慮縮小稜鏡或雙凸透鏡的構造的方法，但 存在如下的問4 .需要幾μιη的構造，不論於製造模具方 面，還是於使料板實際成型方面均困難，成為成i上 升的主要原因。 另外’當使LED與導光板的端面相向而配置成陣列 狀，並將其用作光源時，若縮小鄰接的LED間的距離則 可減少自煮光單元射出的照明光的亮度不均，但因led的 搭載個數增多，故存在消耗電力變高、且亦成為成本上升 的主要原因等問題。 【發明内容】 本發明的目的在於解決上述先前技術的問題，提供如 下的導光板.形狀為大型且薄型，光的利用效率高，可射 出亮度不均少的光，且可獲得對大晝面的薄型液晶電視機 所要求的畫面的中央部附近比周邊部明亮的分布，即所謂 的中間高或吊鐘狀的明亮度的分布。 另外，本發明的另一目的在於提供如下的導光板：可 減少所射入的光自光射入面射出的回光、或被框體覆蓋而 未得以利用的來自光射入面附近的區域的射出光，而提昇 自光射出面的有效區域射出的光的利用效率。 另外，本發明的另一目的在於提供如下的導光板：可 使所射入的光於光射入面附近充分地擴散，而防止於自光 射入面附近射出的射出光中看到因光源的配置間隔等而引 201248270 4201 lpif 起的明線（暗線、不均）。 為了解決上述課題，本發明提供一種導光板，其包括： 矩形狀的光射出面；設置於光射出面的端邊侧、且射入在 與光射出面大致平行的方向上前進的光的至少丨個光射入 面；與光射出面為相反側的背面；以及分散於内部的散射 粒子，其特徵在於：具有在大致垂直於光射出面的方向上 重豎且散射粒子的粒子濃度不同的2層以上的層，2層以 上的層的在大致垂直於光射出面的方向上的厚度各自變 化，合成粒子浪度以在垂直於光射入面的方向上，具有光 射入面側的第1極大值、及位於比第丨極大值更遠離光射 入面的位置且大於第1極大值的第2極大值的方式變化， 且光射入面為在與光射入面的長邊方向平行的方向上，形 成有具有規定的週期構造的切削研磨面的粗面。 此處’較佳為2層以上的層包含光射出面侧的第1層、 及散射粒子的粒子濃度高於第1層的背面侧的第2層這2 層，且在垂直於光射入面的方向上，第2層的厚度以隨著 遠離光射入面而暫時變厚，於變薄之後再次變厚的方式連 續地變化。 另外’為了解決上述課題，本發明提供一種導光板， 其包括：矩形狀的光射出面；設置於光射出面的端邊侧、 且射入在與光射出面大致平行的方向上前進的光的至少1 個光射入面；與光射出面為相反侧的背面；以及分散於内 部的散射粒子；其特徵在於：具有在大致垂直於光射出面 的方向上重疊且散射粒子的粒子濃度不同的2層以上的 11 201248270 HZ.UI ipif 層，2層以上的層的在大致垂直於光射出面的方向上的厚 度各自變化，合成粒子濃度以在垂直於光射入面的方向 上，具有配置於光射入面側的極小值、及位於比極小值更 退離光射入面的位置的第2極大值的方式變化，且光射入 面為在與光射入面的長邊方向平行的方向上，形成有具有 規定的週期構造的切削研磨面的粗面。 此處’較佳為2層以上的層包含光射出面侧的第丨層、 及散射粒子的粒子濃度高於第1層的背面側的第2層這2 層，且在垂直於光射入面的方向上，第2層的厚度以隨著 遠離光射入面而暫時變薄，然後變厚的方式連續地變化 另外，較佳為光射入面為設置於光射出面的相向的2 個端邊側的2個光射入面，且於2個光射入面各自 有第1極大值。 ' 另外’較佳為第2層的厚度於光射出面的中央部最厚。 或者，較佳為光射入面設置於光射出面的丨個+ 側，且具有1個第丨極大值。 响遌 長邊方向 的均方根 另外，較佳為光射入面為形成有形成在與其 正交的短邊方向上的線狀的週期構造的粗面。 另外，較佳為形成於光射入面的切削研磨面 斜率為0.25以上、4.5以下。 分散佳為散射粒子為混合有粒徑不同的粒子的多 另外’較佳為背面為平行於光射出面的平面。 另外’為了解虹述課題，本發明提供—種導光板的 12 201248270 4201 lpif 製造方法’其作為上述任—項所述之導光板的製造方法， 其特徵在於：使包括散射粒子的粒子濃度不同的2層以上 的層、光射出面、及未形成粗面的光射入面的導光板成形 後，利用機械加工於未形成粗面的光射入面上形成切削 磨面。 此處’較佳為機械加工為細線加工。 或者’較佳為機械加工為如下的加工：於銳床、數控 鉋刮機（Numerical Control Router )、或刨機中，控制其刃 具的移動速度及旋轉速度，並控制導光板的未形成粗面的 光射入面與77具的接觸週期，利制具於未形成粗面的光 射入面上形成切削研磨面。 另外，為了解決上述課題，本發明提供一種面狀照明 裝置，其特徵在於包括：上述任一項所述之導光板；以及 與该導光板的光射入面相向、且沿其長邊方向配置的 單元。 ’ 此處，較佳為光源單元包括與光射入面相向、且於光 ' 射入面的長邊方向上等間隔地排列的點光源， ._切猶。 另外’較佳為將點光源的於排列方向上的長度設為2 瓜111〜4 mm，將形成於光射入面的切削研磨面的週期構造 的週期設為5 μιη〜0.4 mm。 ’ [發明的效果] _根據本發明，導光板的形狀為薄型，且光的利用效率 高，可射出亮度不均少的光，可獲得對大晝面的薄型液晶 13 201248270 4201 lpif 電視機所要求的畫面的中央部附近比周邊部明亮的分布， 即所谓的中間高或吊鐘狀的明亮度的分布。 另外，根據本發明，因降低光射入面附近的散射粒子 的濃度，故可減少自光射入面射出的回光、或被框體覆蓋 而未得到利用的來自光射入面附近的區域的射出光，從而 了長：幵自光射出面的有效區域射出的光的利用效率。 另外，根據本發明，於光射入面附近具有合成粒子濃 度的第,1極大值，且光射入面為在與上述光射入面的長邊 方向平行的方向上形成有具有規定的週期構造的切削研磨 面的粗面，因此可使自光射人面射人的光充分地擴散，並 可防止於絲人面附近產生因光_配置間隔㈣引起的 明線（暗線、不均）。 【實施方式] 以下’根據隨附圖式所示的較佳實施形態對使用本發 明的導光板的面狀照明裝置進行詳細說明。 圖1是表示具備使用本發明的導光板的面狀照明裝置 的液晶顯示裝置雜略社體圖，圖2是圖i所示的液晶 顯不裝置的II-II線剖面圖。 ’圖3 (A)疋圖2所示的面狀照明裝置（以下亦 ， 光單元」）的III-III線箭視圖，圖3 (B)是圖3 (A)的線剖面圖。 一，晶顯示裝置1G包括：背光單元2()、配置於該背光 早几❼光射出面側的液晶顯示面板12、以及對液晶顯 不面板12進行驅動的驅動單元14。再者，於圖i中，為 201248270 42011pif 了表不月光早元的構成而省略了液晶顯不面板12的_立p 分的圖示。 液晶顯示面板12中’對事先於特定的方向上排列的液 晶分子局部地施加電場來改變該分子的排列，並利用液曰曰 胞（cell)内產生的折射率的變化，將文字、圖形、圖像^ 顯不於液晶顯示面板12的表面上。 驅動單元14對液晶顯示面板12内的透明電極施加電 壓，從而改變液晶分子的朝向並對透過液晶顯示面板12 的光的透過率進行控制。 背光單元20為自液晶顯示面板12的背面對液晶顯示 面板I2的整個面騎光的照明裝置，且具有缝晶顯示面 板12的圖像顯示面大致相同形狀的光射出面2如。 如圖卜圖2、圖3⑷及圖3⑻所示，本實施形 態中的背光單元20包括：照明裝置本體24，其具有2個 光源單元28、導光板30及光學構件單元32;以/及/框體％， 其具有下部框體42、上部框體44、折返構件46及支撐構 件48。另外，如圖}所示，於框體26的下部框體42的背 側安裝有電源收納部49，該電源收納部49收納對光源單 元28供給電力的多個電源。 以下對構成背光單元20的各構成零件進行說明。 照明裝置本體24包括：統單元Μ，其射出光；導 光板3=其使自光源單元28射出的光作為面狀的光射出； 單元32，其使自導光板3〇射出的光散射或 擴政而父成…、不均（n〇 mura )的光。 15 201248270 4201 lpif 首先，對光源單元28進行說明。 圖4 (A)是表示圖1及圖2所示的背光單元20的光 源單元28的概略構成的概略立體圖，圖4 (B)是僅將圖 4 (A)所示的光源單元28的1個LED晶片放大表示的概 略立體圖。 如圖4 (A)所示’光源單元28包括多個發光二極體 的晶片（以下稱作「LED晶片」）50、及光源支撐部52。 LED晶片50為於射出藍色光的發光二極體的表面塗 佈螢光物質而成的晶片，其具有規定面積的發光面58,且 自該發光面58射出白色光。 即，若自LED晶片50的發光二極體的表面射出的藍 色光透過螢光物質，則螢光物質發出螢光。藉此，由發光 二極體射出的藍色光與螢光物質發出螢光而射出的光生成 白色光，並自LED晶片50射出該白色光。 此處，作為LED晶片50，例示於GaN系發光二極體、 InGaN糸發光二極體等的表面塗佈紀紹石權石（Yttrjum Aluminum Garnet，YAG)系螢光物質而成的晶片。 光源支撐部52為一面與導光板3〇的光射入面（30c、 30d)相向而配置的板狀構件。 光源支撐部52在成為與導光板3〇的光射入面（30c、 30d)相向的面的側面，以使多個LED晶片5〇彼此隔開規 定間隔的狀態進行支撐。具體而言，構成光源單元28的多 個LED晶片50沿著後述的導光板3〇的第！光射入面30c 或第2光射入面30d的長邊方向，排列為陣列狀，並固定 201248270 42011pif 於光源支樓部52上。 亦呈支撐部52由銅或料導熱性請的金屬形成，且 4 4散熱裝置的功能’該散熱艘置吸收自LED晶片 生=熱並使向外部擴散。再者，於光源支樓部52 ’置㈣擴大表面積且能夠提高散熱效果的散熱 片，亦可設置將熱傳遞至散熱構件的熱管。 =處’如g 4 (B)所示’本實施形態的LED晶片5〇 八 方形形狀，該長方形形狀是與排列方向正交的方向 上的長度比LED晶# 5G的制方向上的長度短的長方形 形狀，即’後述的導光板30的厚度方向（垂直於光射出面 3〇a的方向）成為短邊的長方形形狀。換言之，當將垂直 於導光板30的光射出面30a的方向上的長度設為a、將排 列方向上的長度設為b時，LED晶片50是變成b>a的形 狀。另外，若將LED晶片50的配置間隔設為q，則q>b。 如此’較佳為LED晶片50的垂直於導光板3〇的光射出面 3〇a的方向上的長度a、排列方向上的長度b、led晶片 50的配置間隔q的關係滿足q>b>a。 藉由將LED晶片50設為長方形形狀，可維持大光量 的輪出，並可實現薄型的光源單元。藉由將光源單元28 加以薄型化，可使背光單元變成薄型。另外，可減少led 晶片的配置個數。 再者’為了可使光源單元28變得更薄型，LED,晶片 5〇較佳為設為將導光板30的厚度方向作為短邊的長方形 形狀，但本發明並不限定於此，亦可使用正方形形狀、圓 17 201248270 外 zmipif 形形狀、多邊形形狀、橢圓形形狀等各種形狀的LED晶片。 其次，對導光板30進行說明。 圖5是表示導光板的形狀的概略立體圖。 如圖2、圖3及圖5所示’導光板3〇包括：長方形形 狀的光射出面30a;於該光射出面3〇a的長邊側的兩端面， 相對於光射出面30a大致垂直地形成的2個光射入面（第 1光射入面30c與第2光射入面30d);以及位於光射出面 30a的相反側’即導光板30的背面側且為平面的背面3〇b。 此處，上述2個光源單元28分別與導光板30的第1 光射入面30c、及第2光射入面3〇d相向而配置。此處， 本實施形態中’在大致垂直於光射出面3〇a的方向上，光 源早元28的LED晶片50的發光面58的長度與第1光射 入面30c、及第2光射入面3〇d的長度為大致相同的長度。 如此，背光單元20是以2個光源單元28夾持導光板 30的方式配置。即，於隔開規定間隔而相向配置的2個光 源單元28之間配置有導光板30。 導光板30是將用以使光散射的散射粒子於透明樹脂 中混煉分散而形成。作為導光板3〇中所使用的透明樹脂的 材料，例如可列舉如聚對苯二甲酸乙二酯（p〇lyethylene terephthalate，PET)、聚丙婦（p〇lypr〇pylene，pp)、聚碳 酸醋（polycarbonate ’ PC )、聚甲基丙烯酸曱酯（p〇lymethyl methacrylate，PMMA)、曱基丙烯酸苄酯、甲基苯乙烯 (methylstyrene，MS )樹脂、或者環烯烴聚合物（Cyd〇〇lefin Polymer’COP)般的光學透明的樹脂。作為於導光板3〇 201248270 4201 lpif ' 政的政射粒子，可使用Tospearl、石夕明、二氧化 矽、錯、介電質聚合物等。 此處’導光板30由2層構造形成’該2層構造為被分 ^射出面、側的第1層60、及背面30b側的第2層62。 右將第1層60與第2層62的邊界設為邊界面z，則第1 層6〇為由光射出面30a、第1光射入面30c、第2光射入 面3〇d、及邊界面z所圍成的剖面的區域，第2層62為鄰 接於第1層的月面側的層，且為由邊界面z與背面3〇b 所圍成的剖面的區域。 若將第1層60的散射粒子的粒子濃度設為Np〇，將第 2層62的散射粒子的粒子濃度設為Npr，則Np〇與Npr 的關係變成NP〇<Npr。即，導光板30中，背面3〇b側的 第2層的散射粒子的粒子濃度高於光射出面側的第丄 層。 另外，當以垂直於光射入面的長邊方向的剖面進行觀 察時’第1層60與第2層62的邊界面2以第2層62自二 等分線α處的光射出面3〇a(即光射出面的中央；）朝第i 光射入面3〇C及第2光射入面施變薄的方^連續地變 化，進而，以於第1光射入面30c及第2光射入面遍附 近暫時變厚，然後再次變薄的方式連續地變化。 具體而言’邊界面z包含導光板3〇的中央部的朝光射 出面30a凸出的轉；順暢地連接於該凸出的曲線的凹陷 的曲線；以及與該凹陷的曲線連接且連接於光射入面 30c、光射入面30d的背面3〇b側的端部的凹陷的曲線。另 201248270 42011pif 外’於光射入面30c、光射入面30d上，第2層62的厚度 變成0。 又 如此’使散射粒子的粒子濃度高於第1層6〇的第2 層的厚度，以具有在光射入面附近暫時變厚的第1極大 值、及在導光板中央部變成最厚的第2極大值的方式連續 地變化，藉此使散射粒子的合成粒子濃度以具有第i光身7 入面及第2光射入面（30c及3〇d)各自的附近的第J極大 值、以及導光板中央部的大於第丨極大值的第2極大值 方式變化。 即，合成粒子濃度的分布是以如下方式變化的曲線： 於導光板30的中央具有成為最大的第2極大值，於其诗 侧，圖示例中，於自中央至光射入面（3〇(1及3〇〇為^备 距離的約2/3的位置處具有極小值，進而於比極小值 近光射入面側具有第1極大值。 再者’於本發明巾，所謂合絲子濃度，是指於自4 射入面朝另-射人面離開的某__位置處，使用在與光射技 面大致垂直的方向上相加（合成）的散雜子量，並將琴 光板視作光射人面的厚度的平板時的散雜子的濃度。 即’於離開光射人面的某-位置處，當將該導光板視W =入面的厚度的-種濃度的平板導光板時，上述合成粒^ 遭f是在減射出面大致垂直的方向上的相加的散射粒^ 的每單位體積的數量、或彳目對於母材的重量百分率。 另外，第2層62的厚度（合成粒子濃度）的第1極j 值的位置疋配置於上部框體44的開口部4如的邊界的位】 20 201248270 4201lpif ί I、光射人面3(M至第1極大值 為止的區域配置於比上部框體44的開口部叫更 形成開口部44a的邊柜部分，因此無助於背光單元如 二即’自光射入面3〇c、光射入面3〇d至第 =的區域為用以使自光射入面射入的光擴散的所謂的 此δ區（rmxing zone) M。另外，比混合區M更靠近導光 板中央部的區域’即與上部框體44的開口部4如相對應的 區域為有效晝面區E，且為有助於背光單元2〇的光的=出 的區域。 如此’藉由將導光板30的合成粒子濃度（第2層的厚 度）設為於中央部具有成為最大的第2極大值的濃度，即 便疋大型且薄型的導光板，亦可使自光射入面、光射 入面30d射入的光到達更遠離光射入面3〇c、光射入面3〇d 的位置為止，從而可使射出光的亮度分布變成中間高的亮 度分布。 另外’藉由在光射入面30c、光射入面30d附近配置 合成粒子濃度的第1極大值，可使自光射入面3〇c、光射 入面30d射入的光於光射入面附近充分地擴散，而防止於 自光射入面附近射出的射出光中看到因光源的配置間隔等 而引起的明線（暗線、不均）。 另外’藉由將比成為合成粒子濃度的第1極大值的位 置更靠近光射入面30c、光射入面30d側的區域設為低於 苐1極大值的合成粒子濃度，可減少所射入的光自光射入 面射出的回光、或被框體覆蓋而未得到利用的來自光射入 21 201248270 4'2Ullpif 面附近的區域（混合區M)的射出光，從而可提昇自光射 出面的有效區域（有效晝面區Ε)射出的光的利用效率。 另外，藉由將成為合成粒子濃度的第i極大值的位置 配置於比上部框體44的開口部44a更靠近光射入面3〇c、 光射入面30d側處，可減少被框體覆蓋而未得到利用的來 自光射入面附近的區域（混合區M)的射出光，從而可提 昇自光射出面的有效的區域（有效畫面區E)射出的光的 利用效率。 另外，藉由對邊界面z的形狀進行調整，亦可任意地 . 設定亮度分布（散射粒子的濃度分布），從而可最大限度地 · 幵效率。 另外，因降低光射出面側的層的粒子濃度，故可減少 整體的散射粒子的量’從而亦使成本降低。 再者，於圖示例中，將合成粒子濃度的第丨極大值的 位置配置於上部框體44的開口部44a的邊界的位置處，但 本發明並不限定於此，合成粒子濃度的第丨極大值的位置 只要在上部框體44的開口部44a的邊界的附近，則亦可配 置於開口部44a的内側的位置處，或者亦可配置於上部框 ‘ 體44的具有開口部44a的面的邊框部分（開口部4如的外 側）。即，合成粒子濃度的第丨極大值的位置可配置於有效 畫面區E的位置處，亦可配置於混合區M的位置處。 另外，導光板30藉由邊界面z而被分為第丨層㈨與 第2層62，但第1層60與第2層62僅粒子濃度不同，故 為使相同的散射粒子分散於相同的透明樹脂中的構成，從 22 201248270 4201lpif 而於構造上成為一體。即，導光板3〇於以邊界面z為基準 進行了劃分的情況下，各個H域的粒子濃度不同，但邊界 面z為假想的線’第1層60及第2層62成為一體。 此種導光板30可使用擠出成形法或射出成形法來製 造。 此處’當將導光板加以大型化時、或者如導光板3〇 般減小光射入面附近的合成粒子濃度時，於光射入面附近 谷易產生因LED晶片50間的間隙而引起的亮度不均（螢 光不均）。因此，於本發明中，於光射入面上形成粗面，使 所射入的光擴散來抑制不均的產生。 具體而言，如圖5及圖6所示，於導光板3〇的光射入 面（第1光射入面30c與第2光射入面3〇d)上，在與光 射入面的長邊方向平行的方向上形成有具有規定的週期構 造的切削研磨面66。換言之，切削研磨面66為如下的粗 面：具有多個在垂直於光射出面施的方向上延伸的縱條 紋狀的微細的凹凸，且在與光源單元28的LED晶片5〇 的排列方向平行的方向上具有規定的週期構造。 圖7 (A)及圖7 (B)表示概念性地表示將背光單元 20的一部分放大的概略圖的圖。 形成於導光板30的光射入面30c、光射入面30d上的 切削研磨面66的週期構造於光射入面3〇c、光射入面3〇d 的長邊方向上具有規定的週期構造，因此如圖7(A)所示， 使光朝光射入面3〇c、光射入面3〇d的長邊方向擴散（如 由虛線所示般擴散）’故可減少因LED晶片5〇間的間隙而 23 201248270 4201 lpif 引起的亮度不均。另一方面，如圖7(B)所示，不使光朝 垂直於光射出面3〇a的方向擴散（如由實線所示般導光）。 因此，即便於將導光板加以大型化且薄型化的情況 下，亦可抑制光射入面30c、光射入面30d附近的亮度不 均，且可將射入至導光板30的光引導至内部為止。另外， 由於不朝與導光板的光射出面30a垂直的方向擴散，因此 可將射入至導光板30的光引導至内部為止，即便是大型的 導光板30，亦可射出均勻的光。 此處’本說明書内，將使所射入的光朝光射入面3〇c、 光射入面30d的長邊方向擴散，且不朝與側面平行的方向 擴散稱為「具有指向性」。 如此’於導光板30的光射入面30c、光射入面30d上 形成具有指向性的切削研磨面66 ’因此使所射入的光朝光 射入面30c、光射入面30d的長邊方向擴散，故可抑制光 射入面30c、光射入面30d附近的亮度不均。另外，由於 不朝垂直於光射出面30a的方向擴散’因此可將射入至導 光板30的光引導至内部為止，即便是大型的導光板， 亦可射出均勻的光。 尤其’即便於使用將LED晶片50配置成陣列狀的光 源陣列28，且由LED晶片50間的間隙所引起的不均勻的 光射入的情況下，藉由在導光板30的光射入面30c、光射 入面30d上形成具有週期構造的切削研磨面66，亦可使自 導光板30的光射出面30a射出的光變得均勻，因此可減少 LED晶片50的搭載個數，從而可實現消耗電力的降低或 24 201248270 4201 lpif 成本降低。 另外，當如先前般，為了使射入光擴散而於光射入面 上形成有雙凸透鏡或稜鏡時，隨著將導光板加以薄型化， 光源與導光板的光射入面之間的距離相對地變遠，光的射 入效率下降，因此必須將雙凸透鏡或棱鏡的構造加以小型 化，但製造困難，另外，亦成為成本上升的主要原因。 相對於此，與雙凸透鏡或棱鏡相比，形成於本發明的 導光板3 0上的切削研磨面的凹凸微小，因此可拉近導光板 30的光射入面30c與光源單元28之間的距離’從而可維 持並提昇光利用效率。 此處，將測定本發明的導光板的光射入面上所形成的 切削研磨面的表面粗糙度的結果的一例示於圖12，且將先 前為了抑制自光射出面射出的錢亮度不均，而形成於導 光板的光射入面上的雙凸透鏡構造、棱鏡構造、及矩形狀 的槽構造的一例分別示於圖28〜圖3〇。 圖12 (A)是表示在與光射入面的長邊方向平行的方 向上’測定圖7所示的背光單元2〇的導光板3〇的光射入 面上所形成的切削研磨面66的表面粗糙度的結果的一例 的圖’圖12⑻是將圖12⑷所示的表面粗經度轉換 成傅立葉光譜來麵的圖。U (A)將_設為表面粗 糙度（μη〇,將橫軸設為導光板的光射入面上的位置 (mm) ’圖12 (Β)將縱軸設為相對於表面粗糙度的峰值 的相對強度，將橫軸設為空間頻率 另外，將先前為了抑制自光射出面射出的光的亮度不 25 201248270 ipif 均’而形成於導光板的光射入面上的雙凸透鏡構造的傅立 葉光譜的一例示於圖28 (A)及圖28 (B)，將稜鏡構造的 傅立葉光譜的一例示於圖29 (A)及圖29 (B)，將矩形狀 的槽構造的傅立葉光譜的一例示於圖30(A)及圖30(B)。 於圖28 (A)中表示其傅立葉光譜的雙凸透鏡為如下 的形狀：於光射入面上，沿光射入面的長邊方向週期地形 成有具有在與光射出面垂直的方向上延伸的頂部的凸部。 凸。卩的剖面是半徑為〇 5 mm的半圓狀，且該凸部以1 mm 的間距形成。 於圖28 (B)中表示其傅立葉光譜的雙凸透鏡為如下 的形狀·於光射入面上，沿光射入面的長邊方向週期地形 成，具有在與光射出面垂直的方向上延伸的頂部的凸部。 凸15的α彳面疋半徑為0.025 mm的半圓狀，且該凸部以〇 〇5 mm的間距形成。 . 狀：29 (八）中表示其傅立葉光譜的棱鏡為如下的形 具有在上’沿光射人面的長邊方向地形成有 的剖面是=面垂直的方向上延伸的頂部的凸部。凸部 的間距形:Γ、、2職的三角形形狀，且該凸部以1 mm 狀：於人Ϊ)中表示其傅立葉光譜的棱鏡為如下的形 具有在與光射光射人面的長邊方向獅地形成有 的剖面是高;s：A直的方向上延伸的頂料凸部。凸部 _的間距开Γί m的三角形形狀，且該凸部以⑽3 26 201248270 4201 lpif 於圖30 (A)中表示其傅立葉光譜的矩形狀的槽構造 為如下的形狀.於光射人面上，沿光射人面的長邊方向週 期地形成有具有切辅出面垂直的方向±延伸的頂部的 凸。卩凸σ卩的σ,】面是尚度為1 mm的矩形形狀，且該凸部 以1mm的間距形成。 ° 於圖30 (B)中表示其傅立葉光譜的矩形狀的槽構造 為如下的雜：於光射人面上，沿光射人面的長邊方向週 期地形成有具有在與光射出面垂直的方向上延伸的頂部的 凸部。凸部的剖φ是高度為㈣_的細彡雜，且該凸 部以0.03 mm的間距形成。 如圖28 (A)〜圖30 (B)所示，先前為了抑制光射 入面附，的亮度不均’而形成於摘人面上的雙凸透鏡或 稜鏡等是由離散光譜來表示。由此種離散光譜表示者具有 指向性’可使所射入的光適宜地擴散’並可減少自光 面射出的光的亮度不均。 但是，如上所述，當於光射入面上形成有雙凸透鏡或 稜鏡時，隨著將導光板加以薄型化，光源與導光板的光射 入面之間的距離相對地變遠，光的射入效率下降，因此必 肩將雙凸透鏡或棱鏡的構造加以小型化，但製造困難，另 外，亦成為成本上升的主要原因。 相對於此，於本發明的導光板3〇中，如圖12 (B)所 示’形成於光射入面30d上的切削研磨面60的傅立葉光譜 的包絡線（envelope curve)的形狀雖然是連續的光譜，但 為具有1個陡峭的頂部的形狀，因此與雙凸透鏡或稜鏡同 27 201248270 42011pif 樣地具有指向性，可使所射入的光適宜地擴散，並可減少 自光射出面30a射出的光的亮度不均。 進而，與雙凸透鏡或稜鏡相比，切削研磨面60的凹凸 微小，因此可拉近導光板30的光射入面30c與光源單元 28之間的距離，從而可維持並提昇光利用效率。 此處’作為於導光板30的光射入面30c、光射入面30d 上形成具有週期構造的切削研磨面66的方法，可使用機械 加工。即’形成散射粒子的粒子濃度不同的2層的板狀的 導光板，使具有未形成切削研磨面66 (粗面）的光射入面 30c、光射入面30d的導光板30成形後，可藉由機械加工 而在未形成粗面的光射入面30c、光射入面30d上形成切 削研磨面66。作為此種機械加工，例如可使用藉由刷子或 銼刀等在加工面上形成多個微細的凹凸條的細線 (hairline)加工。或者，亦可實施如下的機械加工：藉由 控制銑床、NC鉋刮機（NC router)、刨機（planer)等機 床的刀具的移動速度及旋轉速度，並控制導光板3〇的未形 成粗面的光射入面30c (3〇d：)與機床的刃具的接觸週期， 而利用機床的刃具於導光板30的未形成粗面的光射入面 3〇c (30d)上形成具有週期構造的切削研磨面66。 利用細線加工、或者控制機床的刃具與光射入面的接 觸週期來於導光板的光射入面上形成切削研磨面的機械加 工的本發明的導光板的製造方法與形成微小的雙凸透 棱鏡的先前的導光板的製造方法相比，製造容易二 本降低。 之成 28 201248270 42Ullpif 此處’切削研磨面66的週期構造的週期較佳為遠大於 可見光的波長（λ=650ηιη)，即大於5 μιη〜6 μιη，且變成 LED晶片50的於光射入面的長邊方向上的長度b的 以下。 然而，用作如本發明般的側光型的背光單元的光源的 LED晶片在考慮了與厚度為2 mm以下的導光板的組合的 情況下，若考慮射入效率，則垂直於光射出面的方向上的 長度a較佳為as〇.7T (丁 ：導光板的厚度）。另外，市售 的LED晶片的發光面的縱橫比為1〜3左右。因此，[ED 晶片的於排列方向上的長度b較佳為2 mm〜4 mm左右。 因此’切削研磨面66的週期構造的週期較佳為〇.4inm以 下。 另外，切削研磨面66的週期構造的均方根斜率較佳為 設為0.25〜4.5的範圍。 若切削研磨面66的表面粗糙度小，則無法使射入光充 分地擴散。另一方面，若使切削研磨面66的表面粗糙度變 得過粗，則射入光容易產生菲涅耳反射，射入效率反而下 降，於整個導光板中看到的光利用效率下降。 因此，藉由將切削研磨面66的表面粗糙度設為上述範 圍，而使射入的光以適宜的範圍朝光射入面3〇c、光射入 面30d的長邊方向擴散，因此可防止光過度擴散而無法到 達導光板30的内部為止。 圖2所示的導光板30中’自光源單元28射出並自第 1光射入面30c及第2光射入面3〇d射入的光藉由導光板 29 201248270 42Ullpif 30的内部所包含的散射體（散射粒子）而散射’並通過導 光板30内部而直接自光射出面3〇a射出、或由背面30b 反射後自光射出面30a射出。此時，亦存在一部分光自背 面30b漏出的情況，但所漏出的光藉由配置於導光板3〇 的背面30b側的反射板34反射後再次射入至導光板3〇的 内部。以下將對反射板34進行詳細說明。 此處’第1層60的散射粒子的粒子濃度Np〇、與第2 層62的散射粒子的粒子濃度Npr的關係較佳為滿足〇 wt〇/0 <Npo<0.15 wt0/〇、且 Npo<Npr<0.8 wt〇/〇。 藉由導光板30的第1層60與第2層62滿足上述關 係，於導光板30的粒子濃度低的第1層6〇中，可使所射 入的光不怎麼散射而將其引導至導光板3〇的内部（中央） 為止，隨著接近導光板的中央，可藉由粒子濃度高的第2 層來使光散射，而增加自光射出面3〇a射出的光的量。即， 可進一步提高光的利用效率，並能夠以適宜的比例使照度 分布變成中間高。 此處’所謂粒子濃度[wt%]，是指散射粒子的重量相對 於母材的重量的比例。 或者’第1層60的散射粒子的粒子濃度]^…、與第2 層62的散射粒子的粒子濃度Npr滿足Np〇=〇 wt%、及〇 〇1 wt%<Npr<0.8 wt%亦較佳。即’亦可不使散射粒子於第1 層60中混煉分散，而以將射入的光引導至導光板3〇的内 部為止的方式，使散射粒子僅於第2層62中混煉分散，隨 著接近導光板的中央而使光進一步散射，從而增加自光射 201248270 4201 lpif 出面30a射出的光。 藉由導光板30的第1層60與第2層62滿足上述關 係，亦可進一步提高光的利用效率，並能夠以適宜的比例 使照度分布變成中間高。 另外’作為於導光板30中混鍊分散的散射粒子，可使 用混合有粒徑不同的粒子的多分散粒子。 通常’作為於導光板中混鍊分散的散射粒子，就導光 板内部的光的散射變得均勻，可提昇光的利用效率的觀點 或不易產生顏色不均的觀點而言，使用粒徑均一 粒子比使用多分散粒子更佳。但是，為了 必須對粒子進行分級，而成為成本上升的主要原因 區域Ϊ 子^發明中’藉由使導光板3G的内部的各 粒和不Γ禮不同的散射粒子，即便於使用混合有 用子的情況下’亦可防止光的利 成本的降低。無需對散射粒子進行分級，而可謀求 子 設為:二當將散射粒子的粒徑的標準偏差 士心㈣:2=滿足3σ值相對於中心粒徑處於 ，的料縣單分散粒 度為幾以厚度並無特別限定，可為厚 的所謂的導光片。作為=;::厚度1 nun以下的膜狀 中混練分散而成的膜狀的導光同的散射粒子於2層 的導先板的製作方法，有如下的方 31 201248270 4201 lpif 法，即利用擠出成型法等來製作成為第工層的含有散射粒 子的基底膜，於所製作的基底膜上塗佈使散射粒子分散而 成的單體樹脂液體（透明樹脂的液體）後，照射紫外線或 可見光，使單體樹脂液體硬化，藉此製作所期望的粒子濃 度的第2層，從而製成膜狀的導光板，除該方法以外，有 2層擠出成形法等。 即便於將導光板設為厚度為1 mm以下的膜狀的導光 片的情況下，藉由設為2層的導光板，亦可進一步提高光 的利用效率’並能夠以適宜的比例使照度分布變成中間高。 此處’於圖示例的導光板30中，邊界面z於自第1 極大值的位置至光射入面30c、光射入面30d為止的區域 中為朝光射出面30a凹陷的曲面，且設為連接於光射入面 30c、光射入面30d的背面30b側的端部的形狀’但本發明 並不限定於此。 圖8 (A)〜圖8 (E)表示本發明的導光板的另一例 的概略圖。 再者，除於圖3所示的導光板30中，變更混合區Μ 中的第1層及第2層的厚度，即自光射入面30c、光射入 面30d至第1極大值的位置為止的邊界面z的形狀以外， 圖8 (A)〜圖8 (E)所示的導光板1〇〇、導光板no、導 光板120、導光板130及導光板140具有與導光板30相同 的構成，因此對相同的部位附上相同的符號，且以下的說 明主要針對不同的部位來進行。 圖8 (A)所示的導光板1〇〇包含第1層102、及粒子 32 201248270 42011pif 濃度高於第1層102的第2層104。混合區μ中的第！層 102與第2層104的邊界面ζ為與第1極大值的位置連接 且朝光射出面30a凸出的曲面，且為連接於光射入面3〇c、 光射入面30d的背面30b側的端部的形狀。 圖8 (B)所示的導光板110包含第1層U2、及粒子 濃度高於第1層112的第2層114。混合區μ中的第i層 112與第2層114的邊界面ζ為連接於第1極大值的位置 以及光射入面30c、光射入面30d之背面30b側之端部的 平面。 圖8 (C)所示的導光板120包含第1層122、及粒子 》辰度咼於第1層122的第2層124。混合區Μ中的第1層 122與第2層124的邊界面ζ為與第1極大值的位置連接 且朝光射出面30a凸出的曲面，且為在混合區μ的大致中 央處連接於背面30b的形狀。 圖8 (D)所示的導光板130包含第1層132、及粒子 濃度高於第1層132的第2層134。混合區Μ中的第1層 132與第2層134的邊界面ζ為與第1極大值的位置連接 且朝光射出面30a凹陷的曲面，且為在混合區μ的大致中 央處連接於背面30b的形狀。 圖8 (E)所示的導光板140包含第1層142、及粒子 濃度咼於第1層142的第2層144。於混合區M中，導光 板140僅包含第1層142。即，邊界面ζ為具有通過第！ 極大值的位置且與光射入面30c、光射入面30d平行的平 面的形狀。 33 201248270 L· X pif 如圖8 (a)〜圖8 (E)所示的導光板般’以第2層 的厚度自第1極大值的位置朝光射入面3〇c、光射入面30d 減小的方式形成邊界面z的形狀，藉此可使自第1極大值 的位置至光射入面30c、光射入面30d側為止的區域（混 合區M)的合成粒子濃度變成低於第1極大值的合成粒子 濃度’可減少所射入的光自光射入面射出的回光、或被框 體覆蓋而未得到利用的來自光射入面附近的區域（混合區 M)的射出光，從而可提昇自光射出面的有效區域（有效 晝面區E)射出的光的利用效率。 再者’形成邊界面z的凹形及凸形的曲面在垂直於光 射入面的長邊方向的剖面中，可為由圓或橢圓的一部分來 表不的曲線’亦可為2次曲線或由多項式表示的曲線，亦 可為將該些加以組合的曲線。 另外’於圖示例中設為如下的構成，即，使散射粒子 的粒子濃度高於第1層6〇的第2層的厚度以具有在光射入 面附近暫時變厚的第丨極大值、及在導光板中央部變成最 厚的第2極大值的方式連續地變化，而使散射粒子的合成 粒子濃度以具有第1光射入面及第2光射入面各自的附近 的第1極大值、及導光板中央部的大於第1極大值的第2 極大值的方式變化，但本發明並不限定於此，亦可設為將 合成粒子濃度的第1極大值配置於光射入面上的構成， 即，設為使合成粒子濃度的分布以在導光板的中央具有成 為最大的第2極大值，在其兩侧具有極小值的方式變化的 曲線。 34 201248270 4201 lpif 圖9表示本發明的導光板的另一例的概略圖。 再者，除於圖3所示的導光板30中變更第1層與第2 層的邊界面z的形狀以外，圖9所示的導光板21〇具有與 導光板30相同的構成’因此對相同的部位附上相同的符 號，以下的說明主要針對不同的部位來進行。 圖9所示的導光板210包含光射出面3〇a側的第1層 212、及粒子濃度高於第1層212的背面3〇b側的第2層 214。第1層212與第2層214的邊界面z的形狀是以如^ 方式連續地變化：第2層214的厚度以於導光片中央部變 成最厚，隨著自中央部朝向光射入面3〇c、光射入面3〇d 而變薄的方式變化後，於光射入面3〇c、光射入面3〇d附 近再次變厚。 具體而言，邊界面z包含導光板3〇的中央部的朝光射 出面30a凸出的曲線，及順暢地連接於該凸出的曲線且連 接於光射入面30c、光射入面30d的凹陷的曲線。 即’合成粒子濃度的分布（pr〇file)是以如下 化的曲線：於導光板的中央具有成為最大的第2極大值， 於其兩侧，圖示例中，於自中央至光射人 約2/3的位置處具有極小值。 距離的 ▲如此，變成以如下方式連續地變化的構成， f间的第2層的厚度以於導光片中央部變成最厚，隨【 十央部朝向光射人面而㈣的方式，於 =欠變T且隨著自光射入面朝向導光板的二面: 5成粒子k度以暫時變低後變高的方式連續地變化，並以 35 201248270 4201 lpif 於導光板的中央部變成最高的方式變化，藉此即便是大型 且薄型的導光板，亦可使自光射入面射入的光到達更遠的 位置為止，並可使射出光的亮度分布變成中間高的亮度分 布。 另外’藉由使光射入面附近的合成粒子濃度高於極小 值’可使自光射入面射入的光於光射入面附近充分地擴 散，而防止於自光射入面附近射出的射出光中看到因光源 的配置間隔等而引起的明線（暗線、不均）。 再者’雖然省略圖示，但於導光板210中，於光射入 面30c、光射入面30d上，在與光射入面的長邊方向平行 的方向上亦形成有具有規定的週期構造的切削研磨面，從 而可減少因LED晶片間的間隙而引起的亮度不均。 另外，於圖示例中，將光射出面3〇a設為平面，但並 不限定於此，亦可將光射出面設為凹面◎藉由將光射出面 d又為凹面’當導光板因熱或濕氣而發生伸縮時，可防止導 光板朝光射出面側翹曲，從而可防止導光板與液晶顯示裝 置12接觸。 ” ~ 另外，於圖示例中，將背面30bS為平面，但並不限 定於此，亦可將背面設為凹面，即朝厚度隨著遠離光射入 面而變薄的方向傾斜的面，或者設為凸面，即朝厚度隨著 遠離光射入面而變厚的方向傾斜的面。 其次’對光學構件單元32進行說明。 光學構件單元32是如下的構件，即用以使自導光板 30的光射出面30a射出的照明光變成更不存在亮度不均及 36 201248270 4201 lpif 照度不均的光，並使該光自照明裝置本體24的光射出面 24a射出’如圖2所示’光學構件單元32包括：擴散片32a， 其使自導光板30的光射出面30a射出的照明光擴散來減少 亮度不均及照度不均；稜鏡片32b，其形成有平行於光射 入面30c、光射入面30d與光射出面30a的切線的微稜鏡 列；以及擴散片32c，其使自稜鏡片32b射出的照明光擴 散來減少亮度不均及照度不均。 作為擴散片32a及擴散片32c、棱鏡片32b，並無特別 限制’可使用公知的擴散片或稜鏡片，例如可使用本案申 請人申請的日本專利特開2005-234397號公報的[0028]〜 [0033]中所揭示的擴散片或稜鏡片。 另外，本實施形態中，利用2片擴散片（擴散片32a 及擴散>{ 32c)、及配置於2片擴散片之間的稜鏡片32b來 構成光學構件單元，但稜鏡片及擴散片的配置順序或配置 數1並無特別限定，另外，稜鏡片、擴散片亦無特別限定， 只要可進一步減少自導光板3〇的光射出面3〇a射出的照明 光的凴度不均及照度不均，則可使用各種光學構件。 例如’作為光學構件’除上述擴散片及稜鏡片以外或 作為替代品，亦可使用對應於亮度不均及照度不均來配置 包含擴散反射體的多個透過率調整體的透過率調整構件。 另外’可將稜鏡片及擴散片各使用1片、或者僅使用2片 擴散片來將光學構件單元變成2層構成。 其次，對照明裝置本體24的反射板34進行說明。 反射板34是為了將自導光板30的背面30b洩漏的光 37 201248270 42011pif 反射並再次射入至導光板3〇而設置，其可提昇光的利用效 率。反射板34是以與導光板30的背面30|3相對應的形狀， 並以覆蓋背面30b的方式形成。本實施形態中，如圖2所 示，導光板30的背面30b形成為平面，即剖面形成為直線 形狀，因此反射板34亦可形成為與該形狀相辅相成的形 狀。 反射板34只要可將自導光板3〇的背面3%洩漏的光 反射，則可由任何材料形成，例如可藉由如下材料來形成： 藉由在PET或PP (聚丙烯）等中將填料混練後延伸來形 成空隙而提高了反射率的樹脂片、紐等在透明^ 白色的樹脂片表面形成有鏡面的片材、鋁等的金屬箔或承 載金屬⑽的·旨片、或者表面具有充分的反射性的金屬 板。 崎 上部引導反射板36在導光板30與擴散片32&之間 即在導光板30的光射出面30a側，分別以覆蓋光源單 28及導光板30的光射出面30a的端部（第j光射入面3 ^的端部及第2光射人面观侧的端部）的方式配置。 上㈣丨導反射板36在與妹方向平行的方向上， ^，光板30的光射出面3〇a的一部分至光源單元^ 標部52的-部分為止進行覆蓋的方式配置。即 上^丨導反射板36分別配置於導光板3〇的兩端部。 如此，藉祕置上部料反射板36,可防止 ^射出的光未射入至導光板％而朝光射出面 38 201248270 4201 lpif 藉此，可使自光源單元2 8射出的光高效地射入至導光 板30的第1光射入面30c及第2光射入面3〇d，從而可提 昇光利用效率。 下部引導反射板38是以覆蓋光源單元μ的—部分的 方式配置於導光板30的背面30b側。另外，下部引導反射 板38的導光板30中心側的端部與反射板34連結。 此處，作為上部引導反射板36及下部引導反射板38， 可使用上述反射板34中所使用的各種材料。 藉由设置下部引導反射板38，可防止自光源單元μ 射出的光未射入至導光板30而向導光板3〇的背面3〇b側 漏出。 藉此’可使自光源單元28射出的光高效地射入至導光 板30的第1光射入面30c及第2光射入面3〇d，從而可提 昇光利用效率。 再者，本實施形態中，使反射板34與下部引導反射板 38連結，但並不限定於此’亦可將反射板34與下部引導 反射板38設為獨立的構件。 此處，上部引導反射板36及下部引導反射板38只要 可使自光源單元28射出的光朝第1光射入面3〇c或第2 光射入面30d侧反射，並使自光源單元28射出的光射入至 第1光射入面30c或第2光射入面30d，且可將射入至導 光板30的光引導至導光板30中心侧，則其形狀及寬度並 無特別限定。 另外，本實施形態中，將上部引導反射板36配置在導 39 201248270 4201 lpif 光板30與擴散片32a之間，但上部引導反射板36的配置 位置並不限定於此’亦可配置於構成光學構件單元32的片 狀構件之間，亦可配置於光學構件單元32與上部框體44 之間。 其次，對框體26進行說明。 如圖2所示，框體26收納並支撐照明裝置本體24， 且由該照明裝置本體24的光射出面24a側與導光板3〇的 背面30b側夾持並固定，其包括下部框體42、上部框體44、 折返構件46、及支撐構件48。 下部框體42為如下的形狀：上表面開放，且包含底面 部、及設置於底面部的四邊並垂直於底面部的側面部。即， 下部框體42為一面開放的大致長方體的箱型形狀。下部框 體42如圖2所示，由底面部及侧面部支撐自上方收納的照 明裝置本體24,並且覆蓋照明裝置本體24的光射出面24a 以外的面，即照明裝置本體24的與光射出面24a為相反側 的面（背面）及側面。 上部框體44為上表面形成有作為開口部的矩形狀的 開口、且下表面開放的長方體的箱型形狀，該矩形狀的開 口比照明裝置本體24的矩形狀的光射出面24a小。 如圖2所示，上部框體44自照明裝置本體24及下部 框體42的上方（光射出面側），將照明裝置本體24及收納 該照明裝置本體24的下部框體42以亦覆蓋其四方的側面 部的方式包覆而配置。 折返構件46是剖面的形狀時常變成相同的凹（u字） 201248270 4201 lpif 型的形狀。即，折返構件46是垂直於延伸方向的剖面的形 狀變成U字形狀的棒狀構件。 如圖2所示，折返構件46嵌插在下部框體42的側面 與上部框體44的側面之間，且u字形狀的一平行部的外 側面與下部框體42的側面部連結，另一平行部的外侧面與 上部框體44的侧面連結。 ' 此處，作為下部框體42與折返構件46的接合方法、 折返構件46與上部框體44的接合方法，可使用利用螺釘 及螺母等的方法、利用黏著劑的方法等各種公知的方法。 、如此，藉由在下部框體42與上部框體44之間配置折 返構件46,可提高框體26的剛性，且可防止導光板3〇翹 曲。藉此，即便於使用例如雖可使無亮度不均及照度不均、 或亮度不均及照度不均少的光高效地射出，但容易產生想 曲的導光㈣情況下’亦可更__正㈣、或可更確 =防止導光板產生㈣，從而可將無亮度不均及照度不 f的光、城少了亮度不均及照度不均_光自光射出 面身+屮。 再者，框體的上部框體、下部赌及折返構件中可使 用金屬、樹脂等各種材料。g〇 輕量且高強度的材料。科作為材料，較佳為使用 另外’本實施形態中，將折 :可將其與上部框體或下部框體形成為:ί 3件:; 设為不設置折返構件的構成。 _ ’、可 支樓構件48為垂直於延伸方向的剖面的形狀相同的 201248270 4201 lpif 棒狀構件。 如圖2所示，支撐構件48配置在反射板34與下部框 體42之間，更具體而言，配置在對應於導光板30的背面 3〇b的第1光射入面30c側的端部及第2光射入面30d側 的端部的位置的反射板34、與下部框體42之間，而將導 光板30及反射板34固定並支撐於下部框體42上。 藉由支撐構件48來支撐反射板34，藉此可使導光板 30與反射板34密接。進而，可將導光板30及反射板34 固定於下部框體42的規定位置。 另外，本實施形態中’將支撐構件設為獨立的構件， 但並不限定於此，亦可將其與下部框體42或反射板34形 成為一體。即，亦可於下部框體42的一部分形成突起部， 並將該突起部用作支撐構件’亦可於反射板34的一部分形 成突起部，並將該突起部用作支撐構件。 另外，配置位置亦無特別限定，可配置在反射板與下 部框體之間的任意的位置，但為了穩定地保持導光板，較 佳為配置於導光板的端部側，即’本實施形態中，配置於 第1光射入面30c附近、第2光射入面3〇d附近。 、 另外，支樓構件48 $形狀並無特別限定，可設為各種 形狀，另外，亦可利用各種材料來製作。例如，可設置多 個支撐構件，並每隔規定間隔來進行配置。 另外亦可將支標構件設為填埋由 形成的空間的整健域的形狀，_，將反射板 = 沿著反射㈣雜，將下部框體_面設為沿著下部框^ 42 201248270 42011pif 的形狀。如此，於藉由支撐構件來支撐反射板的整個面的 情況下，可確實地防止導光板與反射板分離，從而可防止 因反射板反射的光而產生亮度不均及照度不均。 背光單元20基本上如以上般構成。 背光單元20將自分別配置於導光板30的兩端的光源 單元28射出的光射入至導光板30的光射入面（第1光射 入面30c及第2光射入面30d)。自各個面射入的光藉由導 光板30的内部所包含的散射體而散射，並通過導光板3〇 内部而直接自光射出面3〇a射出、或由背面3〇b反射後自 光射出面30a射出。此時，自背面漏出的一部分的光藉由 反射板34反射後再次射入至導光板3〇的内部。 如此，自導光板30的光射出面3〇a射出的光透過光學 構件32後，自照明裝置本體24的光射出面24&射出，而 對液晶顯示面板12進行照明。 液晶顯示面板12藉由驅動單元14並對應於位置來控 制光的透過率’藉此於液晶騎面板12的表面上頻示= 字、圖形、圖像等。 此處’上述實施形態為將2個光源單元配置於導 的2個光射入面的兩側射人，但並不岐於此，亦可 僅將^光料^胁導光_丨個光射人面的單側射 ^本猎由減少光源早_數量而削減零件數，從而可降低 43 201248270 HZUlipif 稱的導光板：具有1個光射入面，且於比光射出面的二等 分線更遠離光射入面的位置處導光板的第2層的厚度成為 最大。 圖10 (A)是表示使用本發明的導光板的另一例的背 光單元的一部分的概略剖面圖。再者，於圖10 (A)所示 的背光單元156中，具有導光板150來代替導光板30,且 僅具有1個光源單元28，除此以外，具有與背光單元20 相同的構成’因此對相同的部位附上相同的符號，以下的 說明主要針對不同的部位來進行。 圖10 (A)所示的背光單元156包括導光板150、及 與導光板150的第1光射入面3〇c相向配置的光源單元28。 導光板150具有作為與光源單元28相向配置的面的第 1光射入面30c、及作為第1光射入面3〇c的相反側的面的 侧面150d。 另外’導光板150由光射出面30a側的第1層152與 背面30b側的第2層154形成。當以垂直於第1光射入面 3〇c的長邊方向的剖面進行觀察時，第1層ι52與第2層 的邊界面z以如下方式連續地變化：以第2層154自 第1光射入面30c朝側面150d變厚的方式變化後，以第2 層154暫時變薄的方式變化，然後以第2層154再次變厚 的方式變化，且第2層154於側面150d側變薄。 具體而言，邊界面z包含側面150d側的朝光射出面 3〇a凸出的曲面、順暢地連接於該凸出的曲面的凹陷的曲 面、及與該凹陷的曲面連接且連接於光射入面30c的背面 201248270 4201lpif 3〇b側的端部的凹陷的曲面。另外，於光射入面上， 第2層154的厚度變成〇。 即，使散射粒子的合成粒子濃度（第2層的厚度）以 具有第1光射入面30c附近的第1極大值及第2極大值的 方式變化，該第2極大值比導光板中央部更靠近側面15〇d 側且大於第1極大值。 另外，雖然省略圖示，但導光板150的合成粒子濃度 的第1極大值的位置是配置於框體的開口部的邊界的位置 處，自光射入面30c至第1極大值為止的區域為用以使自 光射入面射入的光擴散的所謂的混合區M。 如此，於僅使用1個光源單元的單面射入的情況下， 將導光板150的合成粒子濃度（第2層154的厚度）設為 如下的濃度，即於靠近光射入面3〇c的位置處具有第i極 大值，於比中央部更靠近側面15〇d側具有大於第1極大值 的第2極大值的濃度，藉此即便是大型且薄型的導光板， 亦可使自光射入面射入的光到達更遠離光射入面的位置為 止，並可使射出光的亮度分布變成中間高的亮度分布。 另外，藉由將合成粒子濃度的第丨極大值配置於光射 入面附近，可使自光射入面射入的光於光射入面附近充分 地擴散，而防止於自光射入面附近射出的射出光中看到因 光源（LED晶片）的配置間隔等而引起的明線（暗線、不 均）。 另外’藉由將比成為合成粒子濃度的第1極大值的位 置更靠近光射入面側的區域設為低於第丨極大值的合成粒 45 201248270 42unpif 子濃度丄可減少所射入的光自光射入面射出的回光、或被 ，體覆蓋而未得到利用的來自光射入面附近的區域（混合 區⑷的射出光，從而可提昇自光射出面的有效區域（有 效畫面區E)射出的光的利用效率。 再者，雖然省略圖示，但於導光板15〇中，於光射入 面30c上，在與光射入面的長邊方向平行的方向上亦形成 有具有規定的週期構造的切削研磨面，從而可減少因LED 晶片間的間隙而弓丨起的亮度不均。 另外，圖10 (A)所示的背光單元156的導光板15〇 的混合區Μ中的邊界面z的形狀為朝光射出面3〇a凹陷的 曲面，且设為連接於光射入面3〇c、光射入面3〇d的背面 30b側的端部的形狀，但並不限定於此。 圖10 (B)〜圖1〇 (F)表示本發明的導光板的另一 例的概略圖。 再者，除於圖10 (A)所示的背光單元156中，變更 導光板150的混合區Μ中的第丨層152及第2層154的厚 度，即自光射入面30c至第1極大值的位置為止的邊界面 z的形狀以外，圖Η) (B)〜圖1G⑺所示的f光單元Diode)"). Since the cold cathode tube has electrodes formed at both ends, light is not emitted from both ends of the cold cathode tube, and uniform light cannot be emitted. Further, when the LEDs 6 201248270 42Ullpif are arranged in an array with the end faces of the light guide plates and used as a light source, there is a gap between the adjacent LEDs, and the light-emitting surface that emits light is not connected, so that it is impossible to emit uniform light as a light source. Light. In other words, when the light emitted from the light source is not uniform as described above, the light incident from the end surface of the light guide plate is also diffused by the light guide oil, and is diffused by the prism sheet or the diffusion sheet, and is in some kind To the extent that the uniform illumination light is emitted from the backlight unit 7G in the vicinity of the human light portion of the light guide plate, the incident light is emitted from the light exit surface in a state where the incident light is not sufficiently diffused, and thus is emitted from the backlight unit. Illumination light produces uneven brightness. Therefore, in order to suppress unevenness in brightness of the light incident portion of the light guide plate, a backlight unit in which light is diffused by a configuration in which the end surface shape of the light guide plate is a rough surface, a ridge, or a lenticular lens has been proposed. For example, Patent Document 3 discloses a side light type surface light source device that deflects illumination light that is incident on an end surface of a plate-shaped member that is formed to be thinner as it goes away from the end surface, and then The one side of the plate-shaped member is emitted, and the end portions of the end faces are formed so that the incident light incident from the end faces is scattered. Further, Patent Document 4 discloses a side light type surface light source device that repeatedly forms a pair of inclined surfaces having a pair of inclined surfaces substantially perpendicular to the emitting surface on the incident surface, and faces the light source in the light emitting region of the light source. The inclined surface on the center side is increased, and the projections are formed in different shapes so that the inclined surface on the center side of the light source becomes smaller in a region away from the light-emitting region. Patent Document 5 describes a side-light type surface light source device. On the incident surface of the plate-like member, a projection composed of i-pair inclined surface 201248270 ipif is repeatedly formed along the longitudinal direction of the incident surface. 〇·〇_~0.30 μηι w is surrounded by the average roughness of the nose. In the surrounding area, the human face of the illumination light is formed into a coarse lens. Patent Document 7 describes a light guide plate having a predetermined length in the longitudinal direction of the disk light incident surface. The slashing of the periodic structure is formed in the form of a surface of the prior art. [PRIOR ART DOCUMENT] [Patent Document] 文献 文献 文献 文献 文献 7 7 7 7 7 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 113 3] Japanese Patent Laid-Open (four), No. 6 [Patent Document 4] 曰 专利 特 ^ 伽 伽 [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [Patent Document η Japanese Patent Laid-Open No. _182478] However, in the case where the thickness is thinned away from the light source, etc. (4), the backlight unit of _ can be realized = the light efficiency is cold cathode tube Compared with the anti-(four), the problem is that the direct type is poor. In addition, the light guide plate described in Patent Document 2 can be made uniform to some extent by making the shape of the scattered light guiding region convex, but it is not considered to adjust the amount of emitted light. = 8 201248270 4201lpif The shape of the light area. In addition, when the backlight unit is thinned and enlarged, it is necessary to reduce the particle concentration of the scattering particles in order to guide the light into the inside of the light guide plate. Since the vicinity of the light incident surface is not sufficiently diffused, there is a possibility that an open line (dark line, unevenness) due to the arrangement interval of the light source or the like is observed in the emitted light emitted from the vicinity of the light human face. On the other hand, if the particle concentration 散射 of the scattering particles in the region near the light incident surface is 咼, there is a concern that the light incident from the light incident surface is reflected in the region near the light incident surface, and is returned as The light emitted from the light incident surface or the region from the vicinity of the light incident surface that is covered by the frame is increased. Here, when the light guide plate is increased in size, in order to emit uniform light from the light exit surface, it is considered to increase the number of light sources such as LEDs. However, in the liquid crystal display device such as a liquid crystal television, reduction in power consumption, reduction in the number of parts, and the like are required, and the increase in the number of light sources that are increased in size violates this requirement. In order to satisfy such a requirement, as described above, in the prior light guide plate, research has been conducted to form a rough surface, a prism, or the like on the light incident surface. However, these methods are not sufficient to meet the requirements of large size or thin weight, especially. For example, in the method of forming a rough surface on the light incident surface of the light guide plate, since it is easily emitted in the vicinity of the light incident portion, it is difficult to guide the light to the inside in a large light guide plate, and it is not possible to emit light from the light. The surface emits uniform light. On the other hand, in the method of forming a prism or a lenticular lens 201248270 πζυ upif on the light incident surface of the light guide plate, there is a problem that as the light guide plate is thinned, the light source and the light guide surface of the light guide plate are thinned. The distance is relatively farther, and the efficiency of light injection is reduced. In addition, a method of reducing the structure of the 稜鏡 or lenticular lens is considered, but the following problem is required. 4. A structure requiring a few μm is difficult in terms of manufacturing a mold or actually forming a material sheet, and is mainly a rise in i. the reason. In addition, when the LEDs are arranged in an array with the end faces of the light guide plate and used as a light source, if the distance between adjacent LEDs is reduced, the brightness unevenness of the illumination light emitted from the light-cooking unit can be reduced, but Since the number of LEDs is increased, there is a problem that power consumption is high and the cost is also increasing. SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above, and to provide a light guide plate having a large size and a thin shape, high light utilization efficiency, and light having a small unevenness in brightness, and a large surface can be obtained. In the vicinity of the center portion of the screen required for the thin liquid crystal television, the distribution is brighter than the peripheral portion, that is, the distribution of the so-called middle height or bell-shaped brightness. Further, another object of the present invention is to provide a light guide plate which can reduce the return light emitted from the light incident surface or the region from the vicinity of the light incident surface which is covered by the frame and which is not utilized. The light is emitted, and the utilization efficiency of light emitted from the effective area of the light exit surface is improved. Further, another object of the present invention is to provide a light guide plate capable of sufficiently diffusing light incident in the vicinity of a light incident surface and preventing the light source from being seen from the light emitted from the vicinity of the light incident surface. The configuration interval is equal to the bright line (dark line, uneven) from 201248270 4201 lpif. In order to solve the above problems, the present invention provides a light guide plate comprising: a rectangular light exit surface; at least one end side of the light exit surface and incident on at least a light traveling in a direction substantially parallel to the light exit surface a light incident surface; a back surface opposite to the light exit surface; and a scattering particle dispersed inside, characterized by having a particle concentration that is vertically vertical and has a different particle concentration of the scattering particles in a direction substantially perpendicular to the light exit surface a layer having two or more layers, a thickness of two or more layers in a direction substantially perpendicular to a light exit surface, and a composite particle wave having a light incident surface side in a direction perpendicular to the light incident surface The first maximum value and the second maximum value that is located farther from the light incident surface than the second maximum value and larger than the first maximum value, and the light incident surface is on the long side of the light incident surface In the direction in which the directions are parallel, a rough surface of the cutting and polishing surface having a predetermined periodic structure is formed. Here, it is preferable that the layer of two or more layers includes the first layer on the light-emitting surface side and the second layer in which the particle concentration of the scattering particles is higher than the second layer on the back surface side of the first layer, and is perpendicular to the light incident. In the direction of the surface, the thickness of the second layer continuously changes as it goes away from the light incident surface, and becomes thicker after being thinned. In order to solve the above problems, the present invention provides a light guide plate comprising: a rectangular light exit surface; and is disposed on an end side of the light exit surface and incident on a light that advances in a direction substantially parallel to the light exit surface. At least one light incident surface; a back surface opposite to the light exit surface; and scattering particles dispersed inside; characterized by having a particle concentration that overlaps in a direction substantially perpendicular to the light exit surface and different scattering particles 2 layers or more of the 11 201248270 HZ.UI ipif layer, the thickness of the layer of 2 or more layers in the direction substantially perpendicular to the light exit surface is changed, and the composite particle concentration is in a direction perpendicular to the light incident surface, The minimum value of the light incident surface side and the second maximum value of the position which is further away from the light incident surface than the minimum value are changed, and the light incident surface is in the longitudinal direction of the light incident surface. In the parallel direction, a rough surface of the cutting and polishing surface having a predetermined periodic structure is formed. Here, it is preferable that the layer of two or more layers includes the second layer of the light-emitting surface side and the second layer of the scattering particle having a particle concentration higher than that of the back surface of the first layer, and is perpendicular to the light incident. In the direction of the surface, the thickness of the second layer is continuously changed so as to become thinner as it goes away from the light incident surface, and then thickened. Further, it is preferable that the light incident surface is opposed to the light exit surface. The two light incident surfaces on the end side have a first maximum value on each of the two light incident surfaces. Further, it is preferable that the thickness of the second layer is the thickest at the central portion of the light exit surface. Alternatively, it is preferable that the light incident surface is provided on the ++ side of the light exit surface and has one 丨 maximum value. Further, the light incident surface is preferably a rough surface formed with a linear periodic structure formed in a short side direction orthogonal thereto. Further, it is preferable that the slope of the cutting and polishing surface formed on the light incident surface is 0.25 or more and 4.5 or less. Preferably, the scattering particles are a mixture of particles having different particle diameters. Further, the back surface is preferably a plane parallel to the light exit surface. In addition, the present invention provides a method for manufacturing a light guide plate according to any one of the above-mentioned items, which is characterized in that the particle concentration of the scattering particles is different. After forming a light guide plate having two or more layers, a light exit surface, and a light incident surface on which no rough surface is formed, a cutting surface is formed by mechanical processing on a light incident surface on which no rough surface is formed. Here, it is preferred to machine into a fine line. Or 'preferably machined as follows: in a sharp bed, a numerical control router, or a planer, controlling the moving speed and rotational speed of the cutting tool, and controlling the unformed surface of the light guide plate The light incident surface and the contact period of 77 pieces are formed on the light incident surface on which the rough surface is not formed to form a cutting and polishing surface. In order to solve the above problems, the present invention provides a planar illumination device comprising: the light guide plate according to any one of the above aspects; and a light incident surface of the light guide plate and disposed along a longitudinal direction thereof Unit. Here, it is preferable that the light source unit includes a point light source that faces the light incident surface and is arranged at equal intervals in the longitudinal direction of the light incident surface. Further, it is preferable that the length of the point light source in the arrangement direction is set to 2 melon 111 to 4 mm, and the period of the periodic structure of the cutting and polishing surface formed on the light incident surface is set to 5 μm to 0.4 mm. [Effects of the Invention] According to the present invention, the shape of the light guide plate is thin, and the light utilization efficiency is high, and light having a small unevenness in brightness can be emitted, and a thin liquid crystal 13 can be obtained for a large surface. 201248270 4201 lpif television set The vicinity of the central portion of the desired screen is brighter than the peripheral portion, that is, the distribution of the so-called middle height or bell-shaped brightness. Further, according to the present invention, since the concentration of the scattering particles in the vicinity of the light incident surface is lowered, the return light emitted from the light incident surface or the region from the vicinity of the light incident surface which is not covered by the frame can be reduced. The emitted light is thus long: the utilization efficiency of light emitted from the effective area of the light exit surface. Further, according to the present invention, the first maximum value of the composite particle concentration is present in the vicinity of the light incident surface, and the light incident surface is formed to have a predetermined period in a direction parallel to the longitudinal direction of the light incident surface. The rough surface of the ground surface is cut, so that the light emitted from the human face can be sufficiently diffused, and the bright line (dark line, unevenness) caused by the light-arrangement interval (4) can be prevented from occurring near the human face. . [Embodiment] Hereinafter, a planar illumination device using the light guide plate of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. Fig. 1 is a schematic cross-sectional view showing a liquid crystal display device including a planar illumination device using a light guide plate according to the present invention, and Fig. 2 is a cross-sectional view taken along line II-II of the liquid crystal display device shown in Fig. 1. Fig. 3 (A) is a cross-sectional view taken along line III-III of the planar illumination device (hereinafter also referred to as "light unit") shown in Fig. 2, and Fig. 3 (B) is a line sectional view of Fig. 3 (A). First, the crystal display device 1G includes a backlight unit 2 (), a liquid crystal display panel 12 disposed on the light emitting surface side of the backlight, and a driving unit 14 that drives the liquid crystal display panel 12. In addition, in Fig. i, the 201248270 42011 pif shows the configuration of the moonlight early, and the illustration of the liquid crystal display panel 12 is omitted. In the liquid crystal display panel 12, an electric field is locally applied to liquid crystal molecules arranged in a predetermined direction to change the arrangement of the molecules, and the change in refractive index generated in the liquid cell is used to change characters, graphics, The image ^ is not visible on the surface of the liquid crystal display panel 12. The driving unit 14 applies a voltage to the transparent electrode in the liquid crystal display panel 12, thereby changing the orientation of the liquid crystal molecules and controlling the transmittance of light transmitted through the liquid crystal display panel 12. The backlight unit 20 is an illumination device that rides light from the back surface of the liquid crystal display panel 12 to the entire surface of the liquid crystal display panel I2, and has a light exit surface 2 having substantially the same shape as the image display surface of the slit crystal display panel 12. As shown in FIG. 2, FIG. 3 (4) and FIG. 3 (8), the backlight unit 20 of the present embodiment includes an illumination device body 24 having two light source units 28, a light guide plate 30, and an optical member unit 32; The frame body % has a lower frame body 42, an upper frame body 44, a folded-back member 46, and a support member 48. Further, as shown in Fig.}, a power supply accommodating portion 49 for accommodating a plurality of power sources for supplying electric power to the light source unit 28 is attached to the back side of the lower casing 42 of the casing 26. Hereinafter, each component constituting the backlight unit 20 will be described. The illuminating device body 24 includes: a unit unit 射 that emits light; a light guide plate 3=which emits light emitted from the light source unit 28 as a planar light; and a unit 32 that scatters or expands light emitted from the light guide plate 3 Politics and fathers become ..., uneven (n〇mura) light. 15 201248270 4201 lpif First, the light source unit 28 will be described. 4(A) is a schematic perspective view showing a schematic configuration of a light source unit 28 of the backlight unit 20 shown in FIG. 1 and FIG. 2, and FIG. 4(B) is a view only showing the light source unit 28 shown in FIG. 4(A). A schematic perspective view showing an enlarged LED chip. As shown in Fig. 4(A), the light source unit 28 includes a plurality of light-emitting diode wafers (hereinafter referred to as "LED wafers") 50 and a light source supporting portion 52. The LED wafer 50 is a wafer obtained by coating a surface of a light-emitting diode that emits blue light with a fluorescent material, and has a light-emitting surface 58 having a predetermined area, and white light is emitted from the light-emitting surface 58. That is, when the blue light emitted from the surface of the light-emitting diode of the LED wafer 50 passes through the fluorescent material, the fluorescent material emits fluorescence. Thereby, the blue light emitted from the light-emitting diode and the light emitted by the fluorescent material and emitted by the fluorescent material generate white light, and the white light is emitted from the LED wafer 50. Here, as the LED wafer 50, a wafer in which a fluorescent material of Yttrjum Aluminum Garnet (YAG) is coated on the surface of a GaN-based light-emitting diode or an InGaN germanium light-emitting diode is exemplified. The light source supporting portion 52 is a plate-like member that is disposed to face the light incident surfaces (30c, 30d) of the light guide plate 3A. The light source supporting portion 52 is supported on a side surface of the surface facing the light incident surfaces (30c, 30d) of the light guide plate 3A so that the plurality of LED chips 5 are spaced apart from each other by a predetermined interval. Specifically, the plurality of LED chips 50 constituting the light source unit 28 are along the third side of the light guide plate 3 described later! The light incident surface 30c or the second light incident surface 30d is arranged in an array in the longitudinal direction, and the 201248270 42011pif is fixed to the light source branch portion 52. The support portion 52 is also formed of a metal of heat conductivity of copper or material, and the function of the heat sink is absorbed by the LED wafer = heat and diffused to the outside. Further, a heat pipe for expanding the surface area and improving the heat radiation effect in the light source branch portion 52' may be provided with a heat pipe for transferring heat to the heat radiating member. = at the position 'g 4 (B)', the LED chip of the present embodiment has a square shape having a square shape in which the length in the direction orthogonal to the arrangement direction is shorter than the length in the direction of the LED crystal #5G. The rectangular shape, that is, the thickness direction of the light guide plate 30 to be described later (the direction perpendicular to the light exit surface 3A) is a rectangular shape having a short side. In other words, when the length in the direction perpendicular to the light exit surface 30a of the light guide plate 30 is a and the length in the arrangement direction is b, the LED wafer 50 is in the shape of b>a. Further, when the arrangement interval of the LED chips 50 is q, then q > b. Thus, the relationship between the length a in the direction perpendicular to the light exit surface 3a of the light guide plate 3A, the length b in the arrangement direction, and the arrangement interval q of the LED wafer 50 is preferably satisfied as q>b> a. By forming the LED wafer 50 into a rectangular shape, it is possible to maintain a large amount of light and to realize a thin light source unit. By thinning the light source unit 28, the backlight unit can be made thin. In addition, the number of configurations of the led wafer can be reduced. Further, in order to make the light source unit 28 thinner, the LEDs and the wafers 5 are preferably rectangular shapes having the thickness direction of the light guide plate 30 as a short side. However, the present invention is not limited thereto and may be used. Square shape, circle 17 201248270 External zmipif shape, polygonal shape, elliptical shape and other LED chips of various shapes. Next, the light guide plate 30 will be described. Fig. 5 is a schematic perspective view showing the shape of a light guide plate. As shown in FIG. 2, FIG. 3 and FIG. 5, the light guide plate 3 includes a rectangular light-emitting surface 30a, and both end faces on the long side of the light-emitting surface 3a are substantially perpendicular to the light-emitting surface 30a. Two light incident surfaces (first light incident surface 30c and second light incident surface 30d) formed in the ground; and a back surface 3 which is located on the opposite side of the light exit surface 30a, that is, the back surface side of the light guide plate 30 〇b. Here, the two light source units 28 are disposed to face the first light incident surface 30c and the second light incident surface 3〇d of the light guide plate 30, respectively. Here, in the present embodiment, the length of the light-emitting surface 58 of the LED chip 50 of the light source unit 28 in the direction substantially perpendicular to the light exit surface 3〇a is different from the first light incident surface 30c and the second light shot. The length of the entry face 3〇d is approximately the same length. In this manner, the backlight unit 20 is disposed such that the two light source units 28 sandwich the light guide plate 30. That is, the light guide plate 30 is disposed between the two light source units 28 that are disposed to face each other at a predetermined interval. The light guide plate 30 is formed by kneading and scattering scattering particles for scattering light in a transparent resin. Examples of the material of the transparent resin used in the light guide plate 3 include, for example, polyethylene terephthalate (PET), polypropylene (p〇lypr〇pylene, pp), and polycarbonate. (polycarbonate ' PC ), p〇lymethyl methacrylate (PMMA), benzyl methacrylate, methylstyrene (MS) resin, or cycloolefin polymer (Cyd〇〇lefin Polymer' COP) optically transparent resin. As the light guide plate 3〇 201248270 4201 lpif 'political political particles, Tospearl, Shi Ximing, bismuth oxide, erbium, dielectric polymer can be used. Here, the light guide plate 30 is formed of a two-layer structure. The two layers are structured to be divided into an emission surface, a first layer 60 on the side, and a second layer 62 on the back surface 30b side. When the boundary between the first layer 60 and the second layer 62 is set to the boundary surface z on the right, the first layer 6 is the light exit surface 30a, the first light incident surface 30c, and the second light incident surface 3〇d. In the region of the cross section surrounded by the boundary surface z, the second layer 62 is a layer adjacent to the moon surface side of the first layer, and is a region of a cross section surrounded by the boundary surface z and the back surface 3〇b. When the particle concentration of the scattering particles in the first layer 60 is Np〇 and the particle concentration of the scattering particles in the second layer 62 is Npr, the relationship between Np〇 and Npr becomes NP〇. <Npr. In other words, in the light guide plate 30, the particle concentration of the scattering particles of the second layer on the side of the back surface 3〇b is higher than the thickness of the second layer on the light emitting surface side. Further, when viewed in a cross section perpendicular to the longitudinal direction of the light incident surface, the boundary surface 2 of the first layer 60 and the second layer 62 is emitted from the light exit surface 3 of the second layer 62 from the bisector α. 〇a (that is, the center of the light exit surface) is continuously changed toward the ith light incident surface 3〇C and the second light incident surface, and is further changed to the first light incident surface 30c and The second light incident surface is temporarily thickened in the vicinity of the pass, and then continuously changed in a thin manner. Specifically, the 'boundary surface z includes a turn protruding toward the light exit surface 30a of the central portion of the light guide plate 3〇; a curve smoothly connected to the concave portion of the convex curve; and a curve connected to the recess and connected to The light incident surface 30c and the concave curve of the end portion on the back surface 3〇b side of the light incident surface 30d. On the other hand, on the light incident surface 30c and the light incident surface 30d, the thickness of the second layer 62 becomes zero. In addition, the particle thickness of the scattering particles is higher than the thickness of the second layer of the first layer 6〇, and has a first maximum value that is temporarily thickened in the vicinity of the light incident surface and a thickest portion in the central portion of the light guide plate. The second maximum value is continuously changed, whereby the composite particle concentration of the scattering particles is set to the Jth maximum value in the vicinity of each of the i-th body 7 entrance surface and the second light incident surface (30c and 3〇d). And the second maximum value of the central portion of the light guide plate that is larger than the second maximum value. That is, the distribution of the concentration of the synthesized particles is a curve which changes in the following manner: The second maximum value which becomes the largest in the center of the light guide plate 30, on the side of the poem, in the example of the figure, from the center to the light incident surface (3) 〇 (1 and 3〇〇 have a minimum value at a position of about 2/3 of the distance, and further have a first maximum value on the side of the near-light incident surface of the minimum value. The concentration of the filament refers to the amount of the scattered amount that is added (synthesized) in a direction substantially perpendicular to the light-emitting surface at a certain __ position from the four-injection side toward the other-shot surface. The concentration of the dipole when the plate is regarded as the plate of the thickness of the human face. That is, at a certain position away from the human face, when the light guide is regarded as the thickness of the face. In the case of the concentration of the flat light guide plate, the above-mentioned synthetic particles are f per unit volume of the added scattering particles in the direction perpendicular to the exit surface, or the weight percentage of the target to the base material. The position 疋 of the first pole j value of the thickness (synthetic particle concentration) of the second layer 62 is disposed in the opening 4 of the upper housing 44 Position of the boundary] 20 201248270 4201lpif ί I, the light-emitting surface 3 (the region from the M to the first maximum value is disposed in the side cabinet portion which is formed by the opening portion 44a than the opening portion of the upper casing 44, and thus is not helpful The region of the backlight unit such as the 'light-injecting surface 3〇c, the light incident surface 3〇d to the first= is a so-called δ region for diffusing light incident from the light incident surface (rmxing) In addition, the region closer to the central portion of the light guide plate than the mixing region M, that is, the region corresponding to the opening portion 4 of the upper frame 44 is the effective face region E, and contributes to the backlight unit 2〇 In this case, the concentration of the composite particle of the light guide plate 30 (the thickness of the second layer) is set to the concentration at which the central portion has the largest maximum value, even if it is a large and thin guide. The light plate can also cause the light incident from the light incident surface and the light incident surface 30d to reach a position farther away from the light incident surface 3〇c and the light incident surface 3〇d, thereby making the light distribution of the emitted light. The brightness distribution is increased to the middle. In addition, the arrangement is made near the light incident surface 30c and the light incident surface 30d. The first maximum value of the particle concentration allows the light incident from the light incident surface 3〇c and the light incident surface 30d to be sufficiently diffused in the vicinity of the light incident surface, thereby preventing the emission from the vicinity of the light incident surface. In the light, an open line (dark line, unevenness) due to the arrangement interval of the light sources, etc. is seen. In addition, the light is incident on the light incident surface 30c and the light is incident by the position which is the first maximum value of the composite particle concentration. The region on the side of the surface 30d is a composite particle concentration lower than the maximum value of 苐1, and it is possible to reduce the return light emitted from the light incident surface or the light from the light incident. 201248270 4'2Ullpif The area near the surface (mixing zone M) emits light, which improves the utilization efficiency of light emitted from the effective area (effective surface area) of the light exit surface. In addition, by arranging the position which is the ith maximum value of the composite particle concentration closer to the light incident surface 3〇c and the light incident surface 30d than the opening 44a of the upper housing 44, the frame can be reduced. The light emitted from the region (mixing region M) near the light incident surface that is not used is improved, and the utilization efficiency of light emitted from the effective region (effective image region E) of the light exit surface can be improved. Further, by adjusting the shape of the boundary surface z, it is also possible to arbitrarily set the luminance distribution (concentration distribution of the scattering particles), thereby maximizing the efficiency. Further, since the particle concentration of the layer on the light-emitting surface side is lowered, the amount of the entire scattering particles can be reduced, which also lowers the cost. In the example of the drawing, the position of the third largest value of the composite particle concentration is disposed at the position of the boundary of the opening 44a of the upper frame 44. However, the present invention is not limited thereto, and the concentration of the synthesized particles is the same. The position of the maximum value of the crucible may be disposed in the vicinity of the boundary of the opening 44a of the upper casing 44, or may be disposed at the inner side of the opening 44a, or may be disposed in the upper frame 'body 44 having the opening 44a. The frame portion of the face (the outer side of the opening portion 4). That is, the position of the third maximum value of the synthesized particle concentration may be disposed at the position of the effective picture area E or at the position of the mixed area M. Further, the light guide plate 30 is divided into the second layer (9) and the second layer 62 by the boundary surface z. However, since the first layer 60 and the second layer 62 have different particle concentrations, the same scattering particles are dispersed in the same manner. The structure in the transparent resin is structurally integrated from 22 201248270 4201lpif. In other words, when the light guide plate 3 is divided based on the boundary surface z, the particle concentration of each of the H domains is different, but the boundary surface z is a virtual line. The first layer 60 and the second layer 62 are integrated. Such a light guide plate 30 can be produced by an extrusion molding method or an injection molding method. Here, when the light guide plate is increased in size or when the concentration of the composite particles in the vicinity of the light incident surface is reduced as in the case of the light guide plate 3, the gap between the LED wafers 50 is likely to occur in the vicinity of the light incident surface. Uneven brightness (uneven fluorescence). Therefore, in the present invention, a rough surface is formed on the light incident surface, and the incident light is diffused to suppress the occurrence of unevenness. Specifically, as shown in FIG. 5 and FIG. 6, the light incident surface (the first light incident surface 30c and the second light incident surface 3〇d) of the light guide plate 3〇 is on the light incident surface. A cutting and polishing surface 66 having a predetermined periodic structure is formed in a direction in which the longitudinal direction is parallel. In other words, the cutting and polishing surface 66 is a rough surface having a plurality of fine irregularities extending in a direction perpendicular to the light emitting surface, and is parallel to the arrangement direction of the LED chips 5 of the light source unit 28. The direction has a defined periodic structure. 7(A) and 7(B) are diagrams conceptually showing an enlarged view of a part of the backlight unit 20. The periodic structure of the cutting and polishing surface 66 formed on the light incident surface 30c and the light incident surface 30d of the light guide plate 30 has a predetermined structure in the longitudinal direction of the light incident surface 3〇c and the light incident surface 3〇d. Since the periodic structure is as shown in Fig. 7(A), the light is diffused toward the longitudinal direction of the light incident surface 3〇c and the light incident surface 3〇d (as shown by the broken line). LED chip 5 gap between the turns and 23 201248270 4201 lpif caused uneven brightness. On the other hand, as shown in Fig. 7(B), the light is not diffused in a direction perpendicular to the light exit surface 3a (as shown by a solid line). Therefore, even when the light guide plate is increased in size and thickness, unevenness in brightness in the vicinity of the light incident surface 30c and the light incident surface 30d can be suppressed, and light incident on the light guide plate 30 can be guided to So far inside. Further, since it is not diffused in a direction perpendicular to the light exit surface 30a of the light guide plate, the light incident on the light guide plate 30 can be guided to the inside, and even the large light guide plate 30 can emit uniform light. Here, in the present specification, the light to be incident is diffused toward the longitudinal direction of the light incident surface 3〇c and the light incident surface 30d, and is not diffused in a direction parallel to the side surface. . Thus, the directional cutting surface 66' is formed on the light incident surface 30c and the light incident surface 30d of the light guide plate 30, so that the incident light is directed toward the light incident surface 30c and the light incident surface 30d. Since the side direction is diffused, unevenness in brightness near the light incident surface 30c and the light incident surface 30d can be suppressed. Further, since it is not diffused in a direction perpendicular to the light exit surface 30a, the light incident on the light guide plate 30 can be guided to the inside, and even a large light guide plate can emit uniform light. In particular, even when the light source array 28 in which the LED chips 50 are arranged in an array is used, and uneven light incident due to the gap between the LED chips 50 is used, the light incident surface of the light guide plate 30 is used. 30c, the cutting surface 63 having a periodic structure is formed on the light incident surface 30d, and the light emitted from the light exit surface 30a of the light guide plate 30 can be made uniform. Therefore, the number of the LED chips 50 can be reduced. Achieve reduced power consumption or 24 201248270 4201 lpif cost reduction. Further, when a lenticular lens or a cymbal is formed on the light incident surface in order to diffuse the incident light as before, as the light guide plate is thinned, the light source and the light incident surface of the light guide plate are thinned. Since the distance is relatively long and the efficiency of light incident is lowered, it is necessary to downsize the structure of the lenticular lens or the prism, but it is difficult to manufacture and also causes a cost increase. On the other hand, the unevenness of the cutting and polishing surface formed on the light guide plate 30 of the present invention is smaller than that of the lenticular lens or the prism, so that the light incident surface 30c of the light guide plate 30 and the light source unit 28 can be drawn closer to each other. Distance 'to maintain and enhance light utilization efficiency. Here, an example of the result of measuring the surface roughness of the cutting and polishing surface formed on the light incident surface of the light guide plate of the present invention is shown in FIG. 12, and the brightness of the money previously emitted to suppress the light exiting surface is uneven. An example of the lenticular lens structure, the prism structure, and the rectangular groove structure formed on the light incident surface of the light guide plate is shown in FIGS. 28 to 3B, respectively. Fig. 12 (A) is a view showing a cutting and polishing surface 66 formed on the light incident surface of the light guide plate 3 of the backlight unit 2A shown in Fig. 7 in a direction parallel to the longitudinal direction of the light incident surface. FIG. 12 (8) which is an example of the result of the surface roughness is a figure which converts the surface rough long degree shown in FIG. 12 (4) into the surface of the Fourier spectrum. U (A) sets _ as the surface roughness (μη〇, and sets the horizontal axis as the position (mm) of the light incident surface of the light guide plate.] FIG. 12 (Β) sets the vertical axis with respect to the surface roughness. The relative intensity of the peak, the horizontal axis is the spatial frequency, and the lenticular structure of the lenticular lens formed on the light incident surface of the light guide plate for the purpose of suppressing the brightness of the light emitted from the light exit surface is not 25 201248270 ipif An example of the spectrum is shown in Fig. 28 (A) and Fig. 28 (B), and an example of the Fourier spectrum of the 稜鏡 structure is shown in Fig. 29 (A) and Fig. 29 (B), and the Fourier spectrum of the rectangular groove structure is shown. An example is shown in Fig. 30 (A) and Fig. 30 (B). The lenticular lens whose Fourier spectrum is shown in Fig. 28 (A) has a shape in which the light incident surface is along the longitudinal direction of the light incident surface. A convex portion having a top portion extending in a direction perpendicular to the light exit surface is periodically formed. The convex 卩 section is a semicircular shape having a radius of 〇5 mm, and the convex portion is formed at a pitch of 1 mm. The lenticular lens whose Fourier spectrum is expressed in (B) has the following shape: on the light incident surface, along the length of the light incident surface The direction is periodically formed, and has a convex portion at the top extending in a direction perpendicular to the light exiting surface. The convex surface of the convex surface 15 has a semicircular shape with a radius of 0.025 mm, and the convex portion is formed at a pitch of 〇〇5 mm. Shape: The prism in which the Fourier spectrum is expressed in the following (29) has a convex portion having a top portion which is formed in the direction of the longitudinal direction of the light human face and which is a direction in which the surface is perpendicular to the vertical direction. The pitch shape of the convex portion: the triangular shape of the Γ, 2, and the convex portion in the shape of 1 mm: the prism whose Fourier spectrum is expressed in the human Ϊ) has the following shape and has the long side of the human face with the light illuminating The lion lion is formed with a profile that is high; s: A apex projection extending in a straight direction. The pitch of the convex portion _ is a triangular shape of Γί m, and the convex portion is configured as a shape of a rectangular groove whose Fourier spectrum is represented by (10) 3 26 201248270 4201 lpif in FIG. 30 (A). A convex portion having a top portion extending perpendicular to the direction perpendicular to the auxiliary surface is formed periodically along the longitudinal direction of the light human face. The σ of the convex σ 卩, the surface is a rectangular shape with a degree of 1 mm, and the convex portions are formed at a pitch of 1 mm. The rectangular groove structure whose Fourier spectrum is shown in Fig. 30(B) is a structure in which the light is incident on the human face, and is periodically formed along the longitudinal direction of the light human face to have a light perpendicular to the light exit surface. The convex portion of the top that extends in the direction. The section φ of the convex portion is a fine doping having a height of (4) _, and the convex portion is formed at a pitch of 0.03 mm. As shown in Figs. 28(A) to 30(B), a lenticular lens or a bismuth or the like which has been previously formed on the person's face in order to suppress unevenness in brightness of the light incident surface is represented by a discrete spectrum. Such a discrete spectrum indicates that the directivity 'is allowed to diffuse the incident light appropriately' and the luminance unevenness of the light emitted from the light surface can be reduced. However, as described above, when a lenticular lens or a cymbal is formed on the light incident surface, as the light guide plate is thinned, the distance between the light source and the light incident surface of the light guide plate becomes relatively distant, and the light is relatively long. Since the injection efficiency is lowered, the structure of the lenticular lens or the prism is reduced in size, but the manufacturing is difficult, and the cost is also a major cause. On the other hand, in the light guide plate 3 of the present invention, as shown in FIG. 12(B), the shape of the envelope curve of the Fourier spectrum of the cutting and polishing surface 60 formed on the light incident surface 30d is Continuous spectrum, but with a steep top shape, so it has directivity with the lenticular lens or the same pattern. The 201248270 42011pif sample has directivity, which allows the incident light to diffuse properly and reduces the self-luminous exit surface. The brightness of the light emitted by 30a is uneven. Further, since the unevenness of the cutting and polishing surface 60 is smaller than that of the lenticular lens or the crucible, the distance between the light incident surface 30c of the light guide plate 30 and the light source unit 28 can be made small, and the light use efficiency can be maintained and improved. Here, as a method of forming the cutting and polishing surface 66 having a periodic structure on the light incident surface 30c and the light incident surface 30d of the light guide plate 30, machining can be used. In other words, the plate-shaped light guide plate having two different particle concentrations of the scattering particles is formed, and the light guide plate 30 having the light incident surface 30c and the light incident surface 30d on which the cutting surface 66 (rough surface) is not formed is formed. The cutting and polishing surface 66 can be formed on the light incident surface 30c and the light incident surface 30d where the rough surface is not formed by mechanical processing. As such a machining, for example, a hairline process in which a plurality of fine uneven strips are formed on a machined surface by a brush or a trowel or the like can be used. Alternatively, it is also possible to perform machining by controlling the moving speed and the rotational speed of the tool of a machine tool such as a milling machine, an NC planer, a planer, and the like, and controlling the unformed thickness of the light guide plate 3〇 The surface of the light incident surface 30c (3〇d:) is in contact with the cutting tool of the machine tool, and the cutting tool of the machine tool is formed on the light-injecting surface 3〇c (30d) of the light guide plate 30 which is not formed with a rough surface. A cutting abrasive surface 66 is constructed. A method for manufacturing a light guide plate of the present invention which is machined by a thin wire processing or a contact period between a blade of a machine tool and a light incident surface to form a cutting surface on a light incident surface of the light guide plate, and forms a minute double convexity Compared with the manufacturing method of the prism of the prior light guide plate, the manufacturing is easy to reduce. 28 201248270 42Ullpif Here, the period of the periodic structure of the cutting and polishing surface 66 is preferably much larger than the wavelength of visible light (λ=650ηηη), that is, greater than 5 μm to 6 μm, and becomes the light incident surface of the LED wafer 50. The length of the long side is below the length b. However, in the case of considering a combination with a light guide plate having a thickness of 2 mm or less, the LED wafer used as the light source of the backlight unit of the side light type according to the present invention is perpendicular to the light exit surface in consideration of the injection efficiency. The length a in the direction is preferably as 〇.7T (d: thickness of the light guide plate). Further, the aspect ratio of the light-emitting surface of the commercially available LED chip is about 1 to 3. Therefore, the length b of the [ED wafer in the arrangement direction is preferably about 2 mm to 4 mm. Therefore, the period of the periodic structure of the cutting abrasive surface 66 is preferably 〇.4 inm or less. Further, the root mean square slope of the periodic structure of the cutting and polishing surface 66 is preferably in the range of 0.25 to 4.5. If the surface roughness of the cutting and polishing surface 66 is small, the incident light cannot be sufficiently diffused. On the other hand, if the surface roughness of the cutting and polishing surface 66 is made too thick, Fresnel reflection is likely to occur in the incident light, and the efficiency of the injection is lowered, and the light use efficiency seen in the entire light guide plate is lowered. Therefore, by setting the surface roughness of the cutting and polishing surface 66 to the above range, the incident light is diffused in the longitudinal direction of the light incident surface 3〇c and the light incident surface 30d in an appropriate range. It is prevented that the light is excessively diffused and cannot reach the inside of the light guide plate 30. In the light guide plate 30 shown in FIG. 2, the light emitted from the light source unit 28 and incident from the first light incident surface 30c and the second light incident surface 3〇d is included in the inside of the light guide plate 29 201248270 42Ullpif 30 . The scatterer (scattering particles) is scattered and passes through the inside of the light guide plate 30 and is directly emitted from the light exit surface 3〇a or reflected from the back surface 30b and then emitted from the light exit surface 30a. At this time, a part of the light leaks from the back surface 30b. However, the leaked light is reflected by the reflection plate 34 disposed on the back surface 30b side of the light guide plate 3A, and is again incident on the inside of the light guide plate 3A. The reflector 34 will be described in detail below. Here, the relationship between the particle concentration Np〇 of the scattering particles of the first layer 60 and the particle concentration Npr of the scattering particles of the second layer 62 is preferably 〇wt〇/0. <Npo <0.15 wt0/〇, and Npo <Npr <0.8 wt〇/〇. When the first layer 60 and the second layer 62 of the light guide plate 30 satisfy the above relationship, in the first layer 6 of the light guide plate 30 having a low particle concentration, the incident light can be scattered to the first layer 6 至. The inner portion (center) of the light guide plate 3A can be light-scattered by the second layer having a high particle concentration as it approaches the center of the light guide plate, thereby increasing the amount of light emitted from the light exit surface 3〇a. That is, the light use efficiency can be further improved, and the illuminance distribution can be made intermediate in an appropriate ratio. Here, the term "particle concentration [wt%]" means the ratio of the weight of the scattering particles to the weight of the base material. Alternatively, the particle concentration of the scattering particles in the first layer 60 and the particle concentration Npr of the scattering particles in the second layer 62 satisfy Np 〇 = 〇 wt%, and 〇 〇 1 wt%. <Npr <0.8 wt% is also preferred. In other words, the scattering particles can be kneaded and dispersed in the first layer 60, and the scattering particles can be kneaded and dispersed only in the second layer 62 so that the incident light is guided to the inside of the light guide plate 3〇. The light is further scattered as it approaches the center of the light guide plate, thereby increasing the light emitted from the light-emitting 201248270 4201 lpif exit surface 30a. By satisfying the above relationship between the first layer 60 and the second layer 62 of the light guide plate 30, the light use efficiency can be further improved, and the illuminance distribution can be made intermediate at an appropriate ratio. Further, as the scattering particles dispersed in the mixed chain in the light guide plate 30, polydisperse particles in which particles having different particle diameters are mixed can be used. In general, as a scattering particle in which a mixed chain is dispersed in a light guide plate, uniformity of particle diameter is used in view of uniformity of scattering of light inside the light guide plate, improvement of light use efficiency, or difficulty in color unevenness. Better than using polydisperse particles. However, in order to classify the particles, it is a cause of an increase in cost. In the invention, the particles in the interior of the light guide plate 3G are different from the scattering particles in the light guide plate 3G, even when mixed useful persons are used. In the case of 'can also reduce the cost of light. It is not necessary to classify the scattering particles, but the sub-set can be set as follows: 2. When the standard deviation of the particle diameter of the scattering particles is (4): 2 = the 3σ value is satisfied with respect to the central particle diameter, and the monodisperse particle size of the material is several The thickness is not particularly limited and may be a thick so-called light guide sheet. As a method for producing a two-layer guide plate in which a film-like light-guided scattering particle obtained by kneading in a film shape having a thickness of 1 nun or less is used, the following method 31 201248270 4201 lpif method, that is, utilization A base film containing scattering particles to be a work layer is produced by an extrusion molding method or the like, and a monomer resin liquid (a liquid of a transparent resin) obtained by dispersing scattering particles is applied onto the produced base film, and then irradiated with ultraviolet rays or In the visible light, the monomer resin liquid is cured to prepare a second layer having a desired particle concentration, thereby forming a film-shaped light guide plate. In addition to this method, there are two-layer extrusion molding methods. In other words, when the light guide plate is used as a film-shaped light guide sheet having a thickness of 1 mm or less, it is possible to further improve the light use efficiency by using two light guide plates, and to illuminate at an appropriate ratio. The distribution becomes intermediate high. Here, in the light guide plate 30 of the illustrated example, the boundary surface z is a curved surface that is recessed toward the light exit surface 30a in a region from the first maximum value to the light incident surface 30c and the light incident surface 30d. Further, the shape is connected to the end portion of the light incident surface 30c and the light incident surface 30d on the back surface 30b side. However, the present invention is not limited thereto. 8(A) to 8(E) are schematic views showing another example of the light guiding plate of the present invention. Further, in the light guide plate 30 shown in Fig. 3, the thicknesses of the first layer and the second layer in the mixing region ,, that is, the light incident surface 30c and the light incident surface 30d to the first maximum value are changed. The light guide plate 1A, the light guide plate no, the light guide plate 120, the light guide plate 130, and the light guide plate 140 shown in FIGS. 8(A) to 8(E) have a light guide plate 30 other than the shape of the boundary surface z at the position. The same components are denoted by the same reference numerals, and the following description is mainly directed to different parts. The light guide plate 1A shown in Fig. 8(A) includes the first layer 102 and the particles 32. The thickness of the 201248270 42011 pif is higher than that of the second layer 104 of the first layer 102. The first in the mixing zone μ! The boundary surface 层 of the layer 102 and the second layer 104 is a curved surface that is connected to the first maximum value and protrudes toward the light exit surface 30a, and is connected to the back surface of the light incident surface 3〇c and the light incident surface 30d. The shape of the end of the 30b side. The light guide plate 110 shown in Fig. 8(B) includes a first layer U2 and a second layer 114 having a higher particle concentration than the first layer 112. The boundary surface 第 of the i-th layer 112 and the second layer 114 in the mixing region μ is a plane connected to the first maximum value and the end portion of the light incident surface 30c and the light incident surface 30d on the back surface 30b side. The light guide plate 120 shown in Fig. 8(C) includes a first layer 122 and a second layer 124 of particles constituting the first layer 122. The boundary surface 第 of the first layer 122 and the second layer 124 in the mixing region ζ is a curved surface that is connected to the first maximum value and protrudes toward the light exit surface 30a, and is connected to the approximate center of the mixing region μ. The shape of the back surface 30b. The light guide plate 130 shown in Fig. 8(D) includes a first layer 132 and a second layer 134 having a higher particle concentration than the first layer 132. The boundary surface 第 of the first layer 132 and the second layer 134 in the mixing zone ζ is a curved surface that is connected to the first maximum value and is recessed toward the light exit surface 30a, and is connected to the back surface at substantially the center of the mixing zone μ. 30b shape. The light guide plate 140 shown in Fig. 8(E) includes a first layer 142 and a second layer 144 having a particle concentration of the first layer 142. In the mixing zone M, the light guide plate 140 includes only the first layer 142. That is, the boundary surface is 具有 with the passage! The position of the maximum value and the shape of the plane parallel to the light incident surface 30c and the light incident surface 30d. 33 201248270 L· X pif In the same manner as the light guide plate shown in Fig. 8 (a) to Fig. 8 (E), the light enters the surface 3〇c and the light is incident from the position of the first maximum value by the thickness of the second layer. The shape of the boundary surface z is formed in such a manner that the surface 30d is reduced, whereby the composite particle concentration in the region (mixing region M) from the position of the first maximum value to the light incident surface 30c and the light incident surface 30d side can be changed. The concentration of the synthesized particles lower than the first maximum value can reduce the return light emitted from the light incident surface or the region from the vicinity of the light incident surface that is not covered by the frame (mixing zone M The light is emitted to increase the utilization efficiency of light emitted from the effective area (effective surface area E) of the light exit surface. Further, 'the concave and convex curved surface forming the boundary surface z may be a curve which is represented by a part of a circle or an ellipse in a cross section perpendicular to the longitudinal direction of the light incident surface, or may be a secondary curve. Or a curve represented by a polynomial, or a curve combining the above. In addition, in the example of the drawing, the particle concentration of the scattering particles is higher than the thickness of the second layer of the first layer 6〇 to have a first maximum value which is temporarily thickened near the light incident surface. And the manner in which the second maximum value of the light guide plate becomes the thickest is continuously changed, and the composite particle concentration of the scattering particles is the first in the vicinity of each of the first light incident surface and the second light incident surface. The maximum value and the second maximum value of the central portion of the light guide plate larger than the first maximum value are changed. However, the present invention is not limited thereto, and the first maximum value of the composite particle concentration may be arranged in the light incident. In the configuration of the surface, the distribution of the concentration of the composite particles is changed so as to have a maximum value at the center of the light guide plate and a minimum value on both sides thereof. 34 201248270 4201 lpif FIG. 9 is a schematic view showing another example of the light guide plate of the present invention. In addition, the light guide plate 21A shown in FIG. 9 has the same configuration as that of the light guide plate 30 except that the shape of the boundary surface z between the first layer and the second layer is changed in the light guide plate 30 shown in FIG. The same parts are denoted by the same reference numerals, and the following description is mainly directed to different parts. The light guide plate 210 shown in Fig. 9 includes a first layer 212 on the light-emitting surface 3〇a side and a second layer 214 having a particle concentration higher than the back surface 3〇b side of the first layer 212. The shape of the boundary surface z of the first layer 212 and the second layer 214 is continuously changed in such a manner that the thickness of the second layer 214 becomes the thickest at the central portion of the light guide sheet, and is incident toward the light from the central portion. When the surface 3〇c and the light incident surface 3〇d are thinned, the thickness is increased again in the vicinity of the light incident surface 3〇c and the light incident surface 3〇d. Specifically, the boundary surface z includes a curved line that protrudes toward the light exit surface 30a at the central portion of the light guide plate 3, and is smoothly connected to the curved curve and is connected to the light incident surface 30c and the light incident surface 30d. The curve of the depression. That is, the distribution of the concentration of the synthesized particles (pr〇file) is a curve having the largest 2nd maximum value at the center of the light guide plate, on both sides thereof, in the example of the figure, from the center to the light shooter There is a minimum value at about 2/3 of the position. The ▲ of the distance is configured to continuously change as follows, and the thickness of the second layer between f becomes the thickest at the center of the light guide sheet, and the method is applied to the light source to face the human face (fourth). = under-torque T and with the light-injecting surface facing the two sides of the light guide plate: 5 into a particle, the k-degree is continuously changed in a manner of becoming lower and then becoming higher, and is changed to the central portion of the light guide plate by 35 201248270 4201 lpif The highest mode change allows the light incident from the light incident surface to reach a farther position even in a large and thin light guide plate, and the luminance distribution of the emitted light can be made to have a high intermediate luminance distribution. Further, 'the concentration of the synthetic particles in the vicinity of the light incident surface is higher than the minimum value', the light incident from the light incident surface can be sufficiently diffused near the light incident surface, and prevented from being emitted from the vicinity of the light incident surface. In the emitted light, an open line (dark line, unevenness) due to the arrangement interval of the light sources and the like is seen. In the light guide plate 210, a predetermined period is formed on the light incident surface 30c and the light incident surface 30d in a direction parallel to the longitudinal direction of the light incident surface. The structured cutting surface is configured to reduce unevenness in brightness due to the gap between the LED wafers. Further, in the illustrated example, the light exit surface 3〇a is a flat surface, but the light exit surface may be a concave surface ◎ by making the light exit surface d a concave surface as a light guide plate. When expansion and contraction occurs due to heat or moisture, the light guide plate can be prevented from warping toward the light exit surface side, and the light guide plate can be prevented from coming into contact with the liquid crystal display device 12. Further, in the illustrated example, the back surface 30bS is a flat surface, but the front surface is not limited thereto, and the back surface may be a concave surface, that is, a surface inclined in a direction in which the thickness is thinned away from the light incident surface. Alternatively, it is a convex surface, that is, a surface that is inclined in a direction in which the thickness becomes thicker away from the light incident surface. Next, the optical member unit 32 will be described. The optical member unit 32 is a member for making a self-light guide plate. The illumination light emitted from the light exit surface 30a of 30 becomes less uneven in brightness and light of illuminance unevenness, and the light is emitted from the light exit surface 24a of the illuminating device body 24 'as shown in FIG. 2' The optical member unit 32 includes a diffusion sheet 32a that diffuses illumination light emitted from the light exit surface 30a of the light guide plate 30 to reduce luminance unevenness and illuminance unevenness; the cymbal sheet 32b is formed to be parallel to the light incident surface 30c. a micro-twist line of the tangential line between the light incident surface 30d and the light exit surface 30a, and a diffusion sheet 32c that diffuses the illumination light emitted from the cymbal sheet 32b to reduce luminance unevenness and illuminance unevenness. Diffusion sheet 32c, prism sheet 3 2b, there is no particular limitation that 'a known diffusion sheet or a cymbal sheet can be used, for example, a diffusion sheet or a rib disclosed in [0028] to [0033] of the Japanese Patent Application Laid-Open No. Hei No. 2005-234397 In the present embodiment, the optical member unit is formed by using two diffusion sheets (diffusion sheet 32a, diffusion > {32c) and a sheet 32b disposed between the two diffusion sheets, but the sheet and the diffusion are formed. The arrangement order of the sheets or the number of the arrays 1 is not particularly limited, and the ruthenium sheet and the diffusion sheet are not particularly limited as long as the unevenness of the illumination light emitted from the light exit surface 3〇a of the light guide plate 3〇 can be further reduced. And the illuminance is uneven, various optical members can be used. For example, 'as an optical member', in addition to or as an alternative to the above-mentioned diffusing sheet and the cymbal, it is also possible to use a diffusing reflector in accordance with uneven brightness and illuminance. The transmittance adjusting member of the plurality of transmittance adjusting members. In addition, the optical member unit can be formed into two layers by using one sheet or each of the diffusion sheets. The reflector 34 of the illuminating device body 24 will be described. The reflector 34 is provided to reflect and re-inject the light 37 201248270 42011pif leaking from the back surface 30b of the light guide plate 30 to the light guide plate 3, which can improve light utilization efficiency. The reflector 34 is formed in a shape corresponding to the back surface 30|3 of the light guide plate 30, and is formed to cover the back surface 30b. In the present embodiment, as shown in Fig. 2, the back surface 30b of the light guide plate 30 is formed into a flat surface. That is, since the cross section is formed in a linear shape, the reflecting plate 34 may be formed in a shape complementary to the shape. The reflecting plate 34 may be formed of any material as long as it can reflect light leaking from the back surface 3% of the light guiding plate 3〇, for example, It is formed by a material which is formed by stretching a filler in PET or PP (polypropylene) or the like to form a void, thereby improving the reflectance, and forming a mirror surface on the surface of the transparent white resin sheet. A metal foil such as a sheet or aluminum, a metal sheet carrying the metal (10), or a metal plate having a sufficient surface on the surface. The upper-side guide reflection plate 36 is disposed between the light guide plate 30 and the diffusion sheet 32', that is, on the light-emitting surface 30a side of the light guide plate 30, and covers the end portions of the light-emitting surface 30a of the light source unit 28 and the light guide plate 30 (jth) The light is incident on the surface of the surface 3^ and the end of the second light-emitting surface. The upper (four) 丨 deflector 36 is disposed so as to cover a part of the light exit surface 3〇a of the light plate 30 in a direction parallel to the sister direction to the portion of the light source unit 52. That is, the upper conductive reflectors 36 are respectively disposed at both end portions of the light guide plate 3''. Thus, by placing the upper material reflecting plate 36, it is possible to prevent the light emitted from the light from entering the light guiding plate % and toward the light emitting surface 38 201248270 4201 lpif , whereby the light emitted from the light source unit 28 can be efficiently injected. The first light incident surface 30c and the second light incident surface 3〇d of the light guide plate 30 can improve the light use efficiency. The lower guide reflection plate 38 is disposed on the side of the back surface 30b of the light guide plate 30 so as to cover a portion of the light source unit μ. Further, the end portion of the lower guide reflection plate 38 on the center side of the light guide plate 30 is coupled to the reflection plate 34. Here, as the upper guide reflection plate 36 and the lower guide reflection plate 38, various materials used in the above-described reflection plate 34 can be used. By providing the lower guide reflection plate 38, it is possible to prevent light emitted from the light source unit μ from entering the light guide plate 30 and leaking toward the back surface 3b side of the light guide plate 3A. Thereby, the light emitted from the light source unit 28 can be efficiently incident on the first light incident surface 30c and the second light incident surface 3〇d of the light guide plate 30, whereby the light use efficiency can be improved. In the present embodiment, the reflector 34 is coupled to the lower guide reflector 38. However, the reflector plate 34 and the lower guide reflector 38 may be independent members. Here, the upper guide reflection plate 36 and the lower guide reflection plate 38 can reflect the light emitted from the light source unit 28 toward the first light incident surface 3〇c or the second light incident surface 30d side, and the self-light source unit The light emitted from 28 is incident on the first light incident surface 30c or the second light incident surface 30d, and the light incident on the light guide plate 30 can be guided to the center side of the light guide plate 30, and the shape and width thereof are not particularly limited. limited. Further, in the present embodiment, the upper guide reflection plate 36 is disposed between the guide 39 201248270 4201 lpif light plate 30 and the diffusion sheet 32a, but the arrangement position of the upper guide reflection plate 36 is not limited thereto. The sheet members of the member unit 32 may be disposed between the optical member unit 32 and the upper frame 44. Next, the casing 26 will be described. As shown in FIG. 2, the housing 26 houses and supports the illuminating device body 24, and is sandwiched and fixed by the light emitting surface 24a side of the illuminating device body 24 and the back surface 30b side of the light guiding plate 3A, which includes the lower housing 42. The upper frame 44, the folded-back member 46, and the support member 48. The lower casing 42 has a shape in which the upper surface is open and includes a bottom surface portion and side surface portions which are provided on the four sides of the bottom surface portion and are perpendicular to the bottom surface portion. That is, the lower casing 42 has a substantially rectangular parallelepiped shape in which one side is open. As shown in FIG. 2, the lower casing 42 supports the illuminating device main body 24 housed from above by the bottom surface portion and the side surface portion, and covers the surface of the illuminating device main body 24 other than the light emitting surface 24a, that is, the illuminating device body 24 and the light emitting device. The surface 24a is a surface (back surface) and a side surface on the opposite side. The upper frame body 44 has a box shape in which a rectangular opening as an opening portion and a rectangular parallelepiped opening are formed on the upper surface, and the rectangular opening is smaller than the rectangular light exit surface 24a of the illuminating device main body 24. As shown in FIG. 2, the upper housing 44 is provided above the illuminating device main body 24 and the lower housing 42 (on the light emitting surface side), and the illuminating device main body 24 and the lower housing 42 accommodating the illuminating device main body 24 are also covered. The side portions of the square are covered and arranged. The shape of the cross-sectional member 46 is often the same concave (u-shaped) shape of the 201248270 4201 lpif type. That is, the folded-back member 46 is a rod-shaped member having a U-shape in a shape perpendicular to the cross section in the extending direction. As shown in FIG. 2, the folding member 46 is interposed between the side surface of the lower casing 42 and the side surface of the upper casing 44, and the outer side surface of the parallel portion of the U-shape is connected to the side surface portion of the lower casing 42, and The outer side surface of a parallel portion is coupled to the side surface of the upper frame body 44. Here, as a method of joining the lower frame 42 and the folded-back member 46, and a method of joining the folded-back member 46 and the upper frame 44, various known methods such as a method using a screw, a nut, or the like, and a method using an adhesive can be used. As described above, by arranging the folding member 46 between the lower casing 42 and the upper casing 44, the rigidity of the casing 26 can be improved, and the light guide plate 3 can be prevented from being warped. Therefore, even if light having no unevenness in luminance and unevenness in illumination, or unevenness in luminance and unevenness in illuminance is emitted, for example, it is easy to generate a light guide for the desired curvature (4). _ positive (four), or more accurate = prevent the light guide plate from generating (four), so that there is no uneven brightness and illuminance is not f, the city is less uneven brightness and illuminance _ light from the light to the face + 屮. Further, various materials such as metal and resin can be used for the upper frame, the lower gambling and the folded-back member of the casing. G〇 Lightweight and high strength materials. As a material, it is preferable to use it. In the present embodiment, it is folded: it can be formed with the upper frame or the lower frame: ί3:; The configuration is such that no folding member is provided. _ ', the slab member 48 is a 201248270 4201 lpif rod member having the same shape as a cross section perpendicular to the extending direction. As shown in FIG. 2, the support member 48 is disposed between the reflector 34 and the lower casing 42, and more specifically, at the end of the first light incident surface 30c side corresponding to the back surface 3b of the light guide plate 30. The light guide plate 30 and the reflection plate 34 are fixed to and supported by the lower frame 42 between the reflector 34 at the position of the end portion on the second light incident surface 30d side and the lower frame 42. The reflection plate 34 is supported by the support member 48, whereby the light guide plate 30 and the reflection plate 34 can be brought into close contact with each other. Further, the light guide plate 30 and the reflection plate 34 can be fixed to a predetermined position of the lower casing 42. Further, in the present embodiment, the support member is an independent member. However, the present invention is not limited thereto, and may be integrally formed with the lower frame 42 or the reflection plate 34. That is, a projection may be formed in a part of the lower casing 42 and the projection may be used as a support member. A projection may be formed on a part of the reflection plate 34, and the projection may be used as a support member. In addition, the arrangement position is not particularly limited, and may be disposed at any position between the reflector and the lower casing. However, in order to stably hold the light guide plate, it is preferably disposed on the end side of the light guide plate, that is, the present embodiment. In the vicinity of the first light incident surface 30c and in the vicinity of the second light incident surface 3〇d. Further, the shape of the branch member 48$ is not particularly limited, and may be various shapes, and may be produced by using various materials. For example, a plurality of support members may be provided and arranged at regular intervals. Alternatively, the branch member may be shaped to fill the shape of the entire health of the formed space, _, the reflector plate = along the reflection (four), and the lower frame _ surface is set along the lower frame ^ 42 201248270 42011 pif shape. As described above, when the entire surface of the reflecting plate is supported by the supporting member, it is possible to reliably prevent the light guide plate from being separated from the reflecting plate, and it is possible to prevent unevenness in brightness and unevenness in illuminance due to light reflected by the reflecting plate. The backlight unit 20 is basically constructed as above. The backlight unit 20 injects light emitted from the light source unit 28 disposed at both ends of the light guide plate 30 into the light incident surface (the first light incident surface 30c and the second light incident surface 30d) of the light guide plate 30. The light incident from each surface is scattered by the scatter body included in the inside of the light guide plate 30, and is directly emitted from the light exit surface 3〇a through the inside of the light guide plate 3, or is reflected from the back surface 3〇b. The exit surface 30a is emitted. At this time, a part of the light leaking from the back surface is reflected by the reflecting plate 34 and is incident on the inside of the light guiding plate 3A again. As described above, the light emitted from the light exit surface 3A of the light guide plate 30 passes through the optical member 32, and is emitted from the light exit surface 24& of the illuminating device main body 24 to illuminate the liquid crystal display panel 12. The liquid crystal display panel 12 controls the transmittance of light by the driving unit 14 in accordance with the position, whereby the word on the surface of the liquid crystal panel 12 is displayed as a word, a figure, an image, and the like. Here, in the above embodiment, the two light source units are arranged on both sides of the two light incident surfaces of the guide, but the present invention is not limited thereto, and only the light source may be guided to light. The one-sided shot of the human face is reduced by reducing the number of parts by the number of light sources, so that the number of parts can be reduced, and thus the light guide plate can be lowered. 201248270 HZUlipif: a light entrance surface and a halving point on the light exit surface The thickness of the second layer of the light guide plate at the position where the line is farther away from the light incident surface becomes the largest. Fig. 10 (A) is a schematic cross-sectional view showing a part of a backlight unit using another example of the light guide plate of the present invention. Further, in the backlight unit 156 shown in FIG. 10(A), the light guide plate 150 is provided instead of the light guide plate 30, and has only one light source unit 28, and has the same configuration as the backlight unit 20. The same reference numerals are attached to the same parts, and the following description is mainly directed to different parts. The backlight unit 156 shown in Fig. 10(A) includes a light guide plate 150 and a light source unit 28 disposed to face the first light incident surface 3〇c of the light guide plate 150. The light guide plate 150 has a first light incident surface 30c as a surface facing the light source unit 28, and a side surface 150d as a surface opposite to the first light incident surface 3〇c. Further, the light guide plate 150 is formed by the first layer 152 on the light exit surface 30a side and the second layer 154 on the back surface 30b side. When viewed in a cross section perpendicular to the longitudinal direction of the first light incident surface 3〇c, the boundary surface z of the first layer ι52 and the second layer is continuously changed as follows: the second layer 154 is from the first layer When the light incident surface 30c is changed to the side surface 150d, the second layer 154 is temporarily thinned, and then the second layer 154 is thickened again, and the second layer 154 is changed on the side surface 150d side. thin. Specifically, the boundary surface z includes a curved surface that protrudes toward the light exit surface 3〇a on the side surface 150d side, a curved surface that is smoothly connected to the convex curved surface, and a curved surface that is connected to the concave surface and connected to the light beam. The back surface of the entrance surface 30c is a recessed curved surface at the end of the 3,0b side of the 4,048, lp. Further, on the light incident surface, the thickness of the second layer 154 becomes 〇. In other words, the composite particle concentration (thickness of the second layer) of the scattering particles is changed so as to have the first maximum value and the second maximum value in the vicinity of the first light incident surface 30c, and the second maximum value is larger than the central portion of the light guide plate. It is closer to the side 15〇d side and larger than the 1st maximum. In addition, the position of the first maximum value of the composite particle concentration of the light guide plate 150 is a position that is disposed at a position of the boundary of the opening of the housing, and the area from the light incident surface 30c to the first maximum value. It is a so-called mixing zone M for diffusing light incident from the light incident surface. As described above, when only one light source unit is used for single-sided incidence, the composite particle concentration (thickness of the second layer 154) of the light guide plate 150 is set to a concentration close to the light incident surface 3〇c. The position has an ith maximum value, and has a second maximum value greater than the first maximum value on the side of the side surface 15〇d from the center portion, whereby the large-sized and thin-shaped light guide plate can be made self-light. The light incident on the incident surface reaches a position farther away from the light incident surface, and the luminance distribution of the emitted light can be made to have an intermediate high luminance distribution. In addition, by arranging the 丨maximum value of the concentration of the composite particles in the vicinity of the light incident surface, the light incident from the light incident surface can be sufficiently diffused in the vicinity of the light incident surface to prevent the light from entering the surface. The bright lines (dark lines, unevenness) caused by the arrangement intervals of the light sources (LED chips) and the like are seen in the emitted light emitted from the vicinity. In addition, the area closer to the light incident surface side than the position which becomes the first maximum value of the composite particle concentration is a composite particle 45 which is lower than the 丨 maximum value. 201248270 42unpif sub-concentration 丄 can reduce the incident light The return light emitted from the light incident surface or the region from the vicinity of the light incident surface (the light emitted from the mixed region (4), which is not covered by the body, can enhance the effective area from the light exit surface (effective picture area) E) The efficiency of the light to be emitted is also formed in the light incident surface 30c in the direction parallel to the longitudinal direction of the light incident surface in the light guide plate 15A. The cutting and polishing surface having a predetermined periodic structure can reduce unevenness in brightness caused by the gap between the LED chips. Further, the mixing region of the light guide plate 15 of the backlight unit 156 shown in Fig. 10(A)Μ The shape of the boundary surface z in the middle is a curved surface that is recessed toward the light exit surface 3〇a, and is a shape that is connected to the end portion of the light incident surface 3〇c and the light incident surface 3〇d on the back surface 30b side, but It is not limited to this. Fig. 10 (B) to Fig. 1 (F) show the present invention In addition, in the backlight unit 156 shown in FIG. 10(A), the thicknesses of the second layer 152 and the second layer 154 in the mixing region 导 of the light guide plate 150 are changed, that is, In addition to the shape of the boundary surface z from the position where the light is incident on the surface 30c to the first maximum value, the f-light unit shown in (B) to (1) (7)

If6、貪光單元176、背光單元186、背光單元196及背光-單元206具有與背光單it 156相同的構成，目此對相同的 部位附上相同的符號’且以下的說明主要針對不同的部位 來進行。 圖10 (B)所示的背光單元166的導光板16〇包含第 1層162、及粒子濃度高於第μ 162的第2層164。混合 46 201248270 4201 lpif 區M中的第1们62與第2層164的邊界φζ為與第α 大值的位置連接且朝光射出面30a凸出的曲面，且為連接 於光射入面30c的背面3〇b側的端部的形狀。 圖ίο (c)所示的背光單元176的導光板17〇包含第 1層172、及粒子濃度高於第i層172的第2層174。混合 區Μ中的第1層172與第2層174的邊界面z為與第i極 大值的位置及光射入面30c的背面30b側的端部連接的平 面。 圖10 (D)所示的背光單元186的導光板18〇包含第 1層182、及粒子濃度高於第i層182的第2層184。混合 區Μ中的第1層182與第2層184的邊界面z為與第丄極 大值的位置連接且朝光射出面3〇a凸出的曲面，且為在混 合區Μ的大致中央處連接於背面3〇b的形狀。 圖10 (E)所示的背光單元196的導光板190包含第 1層192、及粒子濃度高於第1層192的第2層194β混合 區Μ中的第1層192與第2層194的邊界面2為與第}極 大值的位置連接且朝光射出面3〇a凹陷的曲面，且為在混 合區Μ的大致中央處連接於背面3〇b的形狀。 圖10 (F)所示的背光單元2〇6的導光板2〇〇包含第 1層202、及粒子濃度高於第1層202的第2層2〇4。於混 合區Μ中，導光板200僅包含第i層2〇2。即，邊界面z 為具有通過第1極大值的位置且與光射人面歎平行的平 面的形狀。 如圖10 (B)〜圖10 (F、邮-k % 、） 所不的導光板般，以第2 47 201248270 Hzunpif 層的厚度自第1極大值的位置朝光射入面30c減小的方式 形成邊界面z的形狀’藉此可使自第1極大值的位置至光 射入面側3 0c為止的區域（混合區Μ )的合成粒子濃度變 成低於第1極大值的合成粒子濃度，可減少所射入的光自 光射入面射出的回光、或被框體覆蓋而未得到利用的來自 光射入面附近的區域（混合區Μ)的射出光，從而可提昇 自光射出面的有效區域（有效晝面區Ε)射出的光的利用 效率。 另外，於圖10 ( Α)所示的背光單元156梠、、τ过， 將導光板150的合成粒子濃度設為如下的濃度，即於靠近 光射入面30c的位置處具有第1極大值，於比中央部更靠 近側面150d側具有大於第1極大值的第2極大值的濃度， 但本發明並不限定於此，亦可設為將第丨極大值配置於光 射入面上的構成，即，設為使合成粒子濃度的分布以於靠 近光射入面30c的位置處具有極小值，於侧面側15〇d具有 第2極大值的方式變化的曲線。 圖11表示使用本發明的導光板的另一例的背光單元 的概略剖面圖。 ▲再者’除於圖1〇 (A)所示的背光單元156中，具有 I更了第1層與第2層的邊界面z的形狀的導光板22〇來 代Ϊ導光板15。以外，圖11所示的背光單元226具有與背 光單元156相同的構成，因此射目同的部位附上相同的符 號’且以下的說聽要針對不_部位來進行。 圖11所不的背光單元226包括導光板220、及與導光 48 201248270 4201 lpif 板22〇的光射入面30c相向配置的光源單元28。 導光板220包含光射出面30a側的第1層222、及粒 子濃度高於第1層222的背面30b侧的第2層224。第1 層222與第2層224的邊界面z的形狀是以如下方式連續 地變化：以第2層224的厚度自光射入面3〇c朝側面15〇d 暫時變薄的方式變化後，以第2層224變厚的方式變化， 且第2層224於側面150d側變薄。 具體而言’邊界面z包含導光板220的光射入面3〇c 側的朝光射出面30a凹陷的曲線、及順暢地連接於該凹陷 的曲線的朝側面150d侧凸出的曲線。 即，合成粒子濃度的分布是以於光射入面側具有極小 值，於側面側具有第2極大值的方式變化的曲線。 如此’於僅使用1個光源單元的單面射入的情況下， 將導光板220的合成粒子濃度（第2層224的厚度）設為 如下的濃度’即於靠近光射入面30c的位置處具有極小 值’於比中央部更靠近侧面15〇d側具有第2極大值的濃 度，藉此即便是大型且薄型的導光板，亦可使自光射入面 射入的光到達更遠離光射入面的位置為止，並可使射出光 的亮度分布變成中間高的亮度分布。 另外，藉由使光射入面附近的合成粒子濃度高於極小 值’可使自光射入面射入的光於光射入面附近充分地擴 政’從而可防止於自光射入面附近射出的射出口中看到因 光源的配置間隔等而引起的明線（暗線、不均 再者’於圖示例中設為如下的構成，即，使垂直於光 49 201248270 ^fzuupif 射入面30c的方向上的第2層224的厚度隨著自第2極大 值朝向側面150d而變薄，但並不限定於此，自第2極大值 至側面150d之間亦能夠以固定的厚度構成。 另外，使用本發明的導光板的背光單元亦不限定於 此，除2個光源單元以外，亦可與導光板的光射出面的短 邊側的側面相向而配置光源單元。藉由增加光源單元的數 量’可提高裝置射出的光的強度。 另外，不僅可自光射出面射出光，亦可自背面側射出 光。 另外將本發明的導光板設為包含散射粒子的粒子濃 度不同的2層的構成，但並不限定於此，亦可設為包含散 射粒子的粒子濃度不同的3層以上的層的構成。 月 [實例] 明 以下，列舉本發明的具體的實例來更詳細地說明本發 [實例] 以I，根據實例來更具體地說明本發明的導光板。 於貫例中，使用圖3所示的形狀的2層的導光板於 5 60的範圍内，以每次5。變更形成於光射人面的切削研 磨面66的表面的平均傾斜角[。]的（各位置處的傾斜角的 絕對值的平均值）來進行模擬。 將導光板的厚度設為2.〇 mm，將第丨層的粒子濃度設 為0.005 Wt%，將第2層的粒子濃度設為〇 275 wt%，將自 光射入面至第1極大值為止的距離設為10mm，將第1極 50 201248270 4201 lpif 大值的位置處的第2層的厚度設為ο.π mm ° 另外，將自光射入面至極小值為止的距離設為10 mm ’將極小值的位置處的第2層的厚度設為0.145 mm。 另外，將自光射入面至第2極大值（導光板中央）為 止的距離設為270 mm，將第2極大值的位置處的第2層 的厚度設為0.8 mm。 另外’將LED晶片的於排列方向上的長度b設為2.2 mm，將垂直於光射出面的方向上的長度a設為丨15mm , 將配置間隔q設為1〇_5 mm來進行測定。 此處’圖12〜圖23分別為表示本發明的導光板的光 射入面的切削研磨面的各實例的表面粗糙度及其傅立葉光 譜的圖（圖表）。於各圖中’（A)是表示用於本測定的導 光板30的光射入面30d上所形成的切削研磨面6〇的在與 光射入面的長邊方向平行的方向上的表面粗糙度的圖， (B)是將（A)所示的表面粗糙度的圖轉換成傅立葉光譜 來表示的圖。 再者，圖示例的導光板30具有2個光射入面〇〇()及 3〇d)，但因構成相同，故為了便於說明以下以光射入 面30c為代表例進行說明。 一實例1中，使用在光射入面上形成有由圖12 (A)所 示的表面_度、及圖12⑻所示的傅立葉光譜所表示 的平均傾斜角為5。的_研磨_導光板，並於光射入面 的長邊方向上測定離光射人面5 _〜7函的位置處的平 均的照度。 51 201248270 4201 lpif 將測定結果示於圖24 (A)。 同樣地’作為實例2 ’使用在光射入面上形成有由圖 13 (A)所示的表面粗糖度、及圖13 (B)所示的傅立葉 光譜所表示的平均傾斜角為1〇。的切削研磨面的導光板， 並測定入光部附近的照度。 作為實例3，使用在光射入面上形成有由圖14 (A) 所示的表面粗糙度、及圖14 (B)所示的傅立葉光譜所表 示的平均傾斜角為15。的切削研磨面的導光板，並測定入 光部附近的照度。 將實例2及實例3的照度的測定結果示於圖24(A)。 作為實例4，使用在光射入面上形成有由圖15 (A) 所示的表面粗糙度、及圖15 (B)所示的傅立葉光譜所表 示的平均傾斜角為20。的切削研磨面的導光板，並測定入 光部附近的照度。 作為實例5，使用在光射入面上形成有由圖16 (A) 所示的表面粗糙度、及圖16 (B)所示的傅立葉光譜所表 示的平均傾斜角為25。的切削研磨面的導光板，並測定入 光部附近的照度。 另外，作為實例6，使用在光射入面上形成有由圖17 (A)所示的表面粗糙度、及圖17 (B)所示的傅立葉光 譜所表示的平均傾斜角為30。的切削研磨面的導光板，並 蜊定照度。 將實例4〜實例6的照度的測定結果示於圖24 (B)。 作為實例7，使用在光射入面上形成有由圖18 (A) 52 201248270 4ZUUpit' 所示的表面粗糕:度、及圖18 ( B )所示的傅立葉光譜所表 示的平均傾斜角為35。的切削研磨面的導光板，並測定入 光部附近的照度。 作為實例8，使用在光射入面上形成有由圖19 (A) 所示的表面粗糙度、及圖19 (B)所示的傅立葉光譜所表 示的平均傾斜角為40。的切削研磨面的導光板，並測定入 光部附近的照度。 另外，作為實例9，使用在光射入面上形成有由圖20 (A)所示的表面粗糙度、及圖20 (B)所示的傅立葉光 譜所表示的平均傾斜角為45。的切削研磨面的導光板，並 測定照度。 將實例7〜實例9的照度的測定結果示於圖24 (C)。 作為實例10，使用在光射入面上形成有由圖21 (A) 所示的表面粗糙度、及圖21 (B)所示的傅立葉光譜所表 示的平均傾斜角為50。的切削研磨面的導光板，並測定入 光部附近的照度。 作為實例11，使用在光射入面上形成有由圖22 (A) 所示的表面粗糙度、及圖22 (B)所示的傅立葉光譜所表 示的平均傾斜角為55。的切削研磨面的導光板，並測定入 光部附近的照度。 另外，作為實例12,使用在光射入面上形成有由圖23 (A)所示的表面粗糙度、及圖23 (B)所示的傅立葉光 譜所表示的平均傾斜角為60。的切削研磨面的導光板，並 測定照度。 53 201248270 4201 lpif 將實例l〇〜實例12的照度的測定結果示於圖24(d)。 圖24 ( A )〜圖24 ( D )是表示貫例1〜實例12的入 光部附近的知、度的測疋結果的圖表。另外，亦表示光射入 面的表面為鏡面時的照度的測定結果作為比較例。 此處’於圖24 (A)中’以虚線表示實例1，以點劃 線表示實例2 ’以雙點劃線表示實例3，以實線表示比較 例。另外，於圖24 (B)中，以虚線表示實例4，以點劃 線表示實例5，以雙點劃線表示實例6，以實線表示比較 例。另外’於圖24 (C)中，以虚線表示實例7，以點劃 線表示實例8，以雙點劃線表示實例9，以實線表示比較 例。另外，於圖24 (D)中，以虛線表示實例1〇，以點劃 線表示實例11，以雙點劃線表示實例12，以實線表示比較 例。 另外，為了評價照度不均，使用所測定的照度的最大 值 Lmax 與最小值 Lmin ’ 算出（Lmax-Lmin ) / ( Lmax+Lmin )(能 見度（visibility))。將所算出的能見度與平均傾斜角的關 係示於圖25。能見度越低，照度的最大值Lmax與最小值 Lmin的相對的差越小，照度不均越小。 進而，根據所測定的照度，以比較例（平均傾斜角〇。） 的光利用效率為基準，求出相對的光的利用效率。將所求 出的光利用效率示於圖26。 如圖25所示，在垂直於光射入面的方向上，於使第J 層與第2層各自的厚度變化的2層的導光板中，在光射入 面上形成切削研磨面，藉此與光射入面為鏡面的導光板相 54 201248270 4201lpif 比 口]减少光射入面附近的昭片 研磨面的平均傾斜角設為10:二、：。以；’ 刀削 減少光射入面附近的照度不均。60以下’可更適宜地 =處’將平均傾斜角與均方根斜率的關係示於圖27。 根據圖27所示關表’若將平均傾斜㈣為1Q。〜6 範圍’則均方根斜率為0.25〜4.5。因此 率設為〇·25〜4.5的範圍，可適宜地減少光射入面= 照度不均而較佳。 另外，於此種範圍内，表面粗糙度的傅立葉光譜的形 狀（圖12 (Β)〜圖23 (Β))為相同的形狀，不同的是表 面形狀的空間頻率。 另外，於此種範圍内，如圖26所示，即便當於光射入 面上形成有切削研磨面時，與光射人面為鏡面的情況相 比’亦為幾％左右的效率下降，大致相同。 以上’對本發明的導光板、面狀㈣裝置及及導光板 的製造方法進行了詳細說明，但本發明並不限定於上述實 施形態，在不脫離本發明的主旨的範圍内亦可進行各種改 良或變更。 【圖式簡單說明】 圖1是表示具備使用本發明的導光板的面狀照明裝置 的液晶顯示裝置的一實施形態的概略立體圖。 圖2是圖1所示的液晶顯示裝置的π_π線剖面圖。 圖3(A)是圖2所示的面狀照明裝置的ni_m線箭視 圖’圖3 (Β)是圖3 (Α)的Β-Β線剖面圖。 55 201248270 42Ullpif 圖4(A)是表示圖1及圖2所示的面狀照明裝置的光 源單元的概略構成的立體圖，圖4 (B)是將圖4 (A)所 示的光源單元的1個LED放大表示的概略立體圖。 圖5是表示圖3所示的導光板的形狀的概略立體圖。 圖6是圖3所示的導光板的部分放大剖面圖。 圖7 (A)及圖7 (B)是將圖3所示的面狀照明裝置 的一部分放大表示的概略圖。 圖8 (A)〜圖8 (E)是表示本發明的導光板的另一 例的概略剖面圖。 圖9疋表示本發明的導光板的另一例的概略剖面圖。 圖10 (A)〜圖1〇 (f)是表示使用本發明的導光板 的另一例的面狀照明裝置的概略剖面圖。 圖11疋表示使用本發明的導光板的另一例的面狀照 明裝置的概略剖面圖。 圖12 (A)是表示在與光射入面的長邊方向平行的方 向上測定圖6所示的面狀照明裝置的導光板上所形成的切 削研磨面的表面粗縫度的結果的圖，圖12 (B)是將圖12 (A)轉換成傅立葉光譜來表示的圖。 圖13 (A)是表示對用於測定的導光板的切削研磨面 的表面粗縫度進行測定的結果的圖，圖13 (B)是將圖13 (A)轉換成傅立葉光譜來表示的圖。 圖14 (A)是表示對用於測定的導光板的切削研磨面 的表面粗缝度進行測定的結果的圖，圖14 (B)是將圖14 (A)轉換成傅立葉光譜來表示的圖。 56 201248270 42011pif 圖15 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖15 (B)是將圖15 (A)轉換成傅立葉光譜來表示的圖。 圖16 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖16 (B)是將圖16 (A)轉換成傅立葉光譜來表示的圖。 圖17 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖17 (B)是將圖17 (A)轉換成傅立葉光譜來表示的圖。 圖18 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖18 (B)是將圖18 (A)轉換成傅立葉光譜來表示的圖。 圖19 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖19 (B)是將圖19 (A)轉換成傅立葉光譜來表示的圖。 圖20 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖20 (B)是將圖20 (A)轉換成傅立葉光譜來表示的圖。 圖21 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖21 (B)是將圖21 (A)轉換成傅立葉光譜來表示的圖。 圖22 (A)是表示對用於測定的導光板的切削研磨面 的表面粗糙度進行測定的結果的圖，圖22 (B)是將圖22 (A)轉換成傅立葉光譜來表示的圖。 57 201248270 HZUl 1 pif 圖23 (A)是表示對用於測定的導光板的切削研磨面 的表面㈣k度it行測定的結果的圖，圖23⑻是將圖μ (A)轉換成傅立葉光譜來表示的圖。 圖 ^ )圖24 (D)是表示所測定的照度的圖表。 圖25疋表:平均傾斜角與能見度的關係的圖表。 圖26是表示光的利用效率的圖表。 圖27是表示平均傾斜角與均方根斜率的關係的圖表。 圖28(A)是雙凸透鏡的一例的光譜分布圖，圖28(B) 是雙凸透鏡的另一例的光譜分布圖。 圖29 (A)是稜鏡的一例的光譜分布圖，圖29 (b) 是稜鏡的另一例的光譜分布圖。 圖30 (A)是矩形狀槽構造的一例的光譜分布圖，圖 30 (B)是矩形狀槽構造的另一例的光譜分布圖。 【主要元件符號說明】 10 :液晶顯示裝置 12 :液晶顯示面板 14 :驅動單元 20、156、166、176、186、196、206、226 :背光單元 (面狀照明裝置） 24 :照明裝置本體 24a、30a :光射出面 26 :框體 28 :光源單元 30、100、110、120、130、140、150、160、170、180、 58 201248270 4201lpif 190、200、210、220 :導光板 30b :背面 30c :第1光射入面 30d :第2光射入面 32 :光學構件單元 32a、32c :擴散片 32b :棱鏡片 34 :反射板 36 :上部引導反射板 38 :下部引導反射板 42 :下部框體 44 :上部框體 44a :開口部 46 :折返構件 48 ’·支撐構件 49 :電源收納部 50 : LED晶片 52 :光源支撐部 58 :發光面 60、102、112、122、132、142、152、162、172、182 192、202、212、222 :第 1 層 62、104、114、124、134、144、154、164、174、184 194、204、214、224 :第 2 層 66 :切削研磨面 59 201248270fIf6, the greedy unit 176, the backlight unit 186, the backlight unit 196, and the backlight unit 206 have the same configuration as the backlight unit 156, and the same reference numerals are attached to the same portions, and the following description mainly refers to different parts. Come on. The light guide plate 16 of the backlight unit 166 shown in Fig. 10(B) includes a first layer 162 and a second layer 164 having a higher particle concentration than the μ 162. Mixing 46 201248270 4201 The boundary φ 第 between the first member 62 and the second layer 164 in the lpif region M is a curved surface that is connected to the position of the α-large value and protrudes toward the light exit surface 30a, and is connected to the light incident surface 30c. The shape of the end of the back side of the 3〇b side. The light guide plate 17 of the backlight unit 176 shown in (c) includes a first layer 172 and a second layer 174 having a higher particle concentration than the i-th layer 172. The boundary surface z between the first layer 172 and the second layer 174 in the mixing zone is a plane that is connected to the position of the i-th pole and the end of the light incident surface 30c on the back surface 30b side. The light guide plate 18 of the backlight unit 186 shown in Fig. 10(D) includes a first layer 182 and a second layer 184 having a higher particle concentration than the i-th layer 182. The boundary surface z between the first layer 182 and the second layer 184 in the mixing zone 为 is a curved surface that is connected to the position of the 丄 maximum value and protrudes toward the light exit surface 3 〇 a, and is substantially at the center of the mixing zone Μ Connected to the shape of the back 3〇b. The light guide plate 190 of the backlight unit 196 shown in FIG. 10(E) includes the first layer 192 and the first layer 192 and the second layer 194 of the second layer 194β mixed region 粒子 having a higher particle concentration than the first layer 192. The boundary surface 2 is a curved surface that is connected to the position of the ninth maximum value and that is recessed toward the light exit surface 3〇a, and has a shape that is connected to the back surface 3〇b at substantially the center of the mixing region Μ. The light guide plate 2 of the backlight unit 2A shown in Fig. 10(F) includes a first layer 202 and a second layer 2〇4 having a higher particle concentration than the first layer 202. In the mixing zone, the light guide plate 200 only includes the i-th layer 2〇2. That is, the boundary surface z is a shape having a plane passing through the first maximum value and being parallel to the plane of the light. As shown in Fig. 10 (B) to Fig. 10 (F, E-k%), the thickness of the second 47 201248270 Hzunpif layer is reduced from the position of the first maximum value toward the light incident surface 30c. By forming the shape of the boundary surface z, the composite particle concentration of the region (mixing zone Μ) from the position of the first maximum value to the light incident surface side 30c can be changed to the composite particle concentration lower than the first maximum value. It is possible to reduce the return light emitted from the light incident surface or the light emitted from the region (mixing zone 附近) from the vicinity of the light incident surface that is not covered by the frame, thereby enhancing the self-lighting The utilization efficiency of light emitted from the effective area (effective surface area) of the exit surface. Further, in the backlight unit 156 梠 and τ shown in FIG. 10 ( Α ), the composite particle concentration of the light guide plate 150 is set to a concentration having a first maximum value at a position close to the light incident surface 30 c. The concentration of the second maximum value larger than the first maximum value is closer to the side surface 150d than the central portion. However, the present invention is not limited thereto, and the second maximum value may be disposed on the light incident surface. In other words, the distribution of the concentration of the synthesized particles has a minimum value at a position close to the light incident surface 30c, and a curve in which the side surface side 15〇d has a second maximum value. Fig. 11 is a schematic cross-sectional view showing a backlight unit using another example of the light guide plate of the present invention. ▲ In addition, in the backlight unit 156 shown in Fig. 1A (A), the light guide plate 22 having the shape of the boundary surface z of the first layer and the second layer is replaced by the light guide plate 15. The backlight unit 226 shown in Fig. 11 has the same configuration as that of the backlight unit 156. Therefore, the same symbol is attached to the same portion and the following is to be performed for the non-part. The backlight unit 226 shown in Fig. 11 includes a light guide plate 220 and a light source unit 28 disposed to face the light incident surface 30c of the light guide 48 201248270 4201 lpif plate 22A. The light guide plate 220 includes a first layer 222 on the light exit surface 30a side and a second layer 224 in which the particle concentration is higher than the back surface 30b side of the first layer 222. The shape of the boundary surface z between the first layer 222 and the second layer 224 is continuously changed in such a manner that the thickness of the second layer 224 is temporarily thinned from the light incident surface 3〇c toward the side surface 15〇d. The second layer 224 is changed in thickness, and the second layer 224 is thinned on the side 150d side. Specifically, the boundary surface z includes a curve which is recessed toward the light exit surface 30a on the light incident surface 3〇c side of the light guide plate 220, and a curved line which is convexly connected to the concave surface toward the side surface 150d side. In other words, the distribution of the concentration of the synthesized particles is a curve which has a minimum value on the light incident surface side and a second maximum value on the side surface side. When the single-surface incident is performed using only one light source unit, the composite particle concentration (thickness of the second layer 224) of the light guide plate 220 is set to a density "that is, close to the light incident surface 30c". The portion having a minimum value 'having a second maximum value closer to the side surface 15〇d side than the central portion allows the light incident from the light incident surface to reach farther even if it is a large and thin light guide plate. The light is incident on the surface, and the luminance distribution of the emitted light can be made to have an intermediate high luminance distribution. In addition, by making the concentration of the synthetic particles in the vicinity of the light incident surface higher than the minimum value, the light incident from the light incident surface can be sufficiently expanded near the light incident surface, thereby preventing the self-lighting surface. The bright line (dark line, unevenness) caused by the arrangement interval of the light sources, etc., is observed in the vicinity of the exiting exit, and is configured as follows in the example of the figure, that is, perpendicular to the light 49 201248270 ^fzuupif injection surface The thickness of the second layer 224 in the direction of 30c becomes thinner from the second maximum value toward the side surface 150d. However, the thickness is not limited thereto, and the thickness may be constant from the second maximum value to the side surface 150d. In addition, the backlight unit using the light guide plate of the present invention is not limited thereto, and the light source unit may be disposed to face the side surface on the short side of the light exit surface of the light guide plate in addition to the two light source units. In addition, the light emitted from the light emitting surface can be emitted from the light emitting surface, and the light can be emitted from the back side. Further, the light guide plate of the present invention is set to have two layers of different particle concentrations including scattering particles. Composition However, the present invention is not limited thereto, and may be a configuration including three or more layers having different particle concentrations of scattering particles. [Examples] Hereinafter, specific examples of the present invention will be described to explain the present invention in more detail. The light guide plate of the present invention will be more specifically described by way of example with reference to an example. In the example, a two-layer light guide plate having the shape shown in Fig. 3 is used in the range of 560, with a change of 5 each time. The average inclination angle of the surface of the cutting surface 66 of the human face is [the average value of the absolute values of the inclination angles at the respective positions). The thickness of the light guide plate is set to 2. 〇mm, The particle concentration of the second layer was set to 0.005 Wt%, the particle concentration of the second layer was set to 〇275 wt%, and the distance from the light incident surface to the first maximum value was set to 10 mm, and the first pole 50 201248270 4201 lpif The thickness of the second layer at the position of the large value is set to ο.π mm °. In addition, the distance from the light incident surface to the minimum value is set to 10 mm 'the second layer at the position where the minimum value is The thickness is set to 0.145 mm. In addition, the light is incident on the surface to the second maximum value (center of the light guide plate). The distance to be stopped is set to 270 mm, and the thickness of the second layer at the position of the second maximum value is set to 0.8 mm. In addition, 'the length b of the LED wafer in the arrangement direction is set to 2.2 mm, which is perpendicular to the light. The length a in the direction of the surface is 丨15 mm, and the measurement is performed by setting the arrangement interval q to 1 〇 5 mm. Here, FIGS. 12 to 23 are cuts showing the light incident surface of the light guide plate of the present invention. A graph (graph) of the surface roughness of each of the polished surfaces and its Fourier spectrum. In each of the drawings, '(A) is a cutting and polishing surface formed on the light incident surface 30d of the light guide plate 30 used for the measurement. (B) is a graph showing the surface roughness in the direction parallel to the longitudinal direction of the light incident surface, and (B) is a graph in which the graph of the surface roughness shown in (A) is converted into a Fourier spectrum. Further, the light guide plate 30 of the illustrated example has two light incident surfaces )() and 3〇d). However, since the configuration is the same, the light incident surface 30c will be described as a representative example for convenience of explanation. In an example 1, the average tilt angle represented by the surface _ degree shown in Fig. 12 (A) and the Fourier spectrum shown in Fig. 12 (8) on the light incident surface was 5. The _grinding_light guide plate measures the average illuminance at the position of the 5 _~7 letter from the human face on the long side of the light incident surface. 51 201248270 4201 lpif The measurement results are shown in Fig. 24 (A). Similarly, as an example 2, an average tilt angle represented by the surface roughness of the surface shown in Fig. 13 (A) and the Fourier spectrum shown in Fig. 13 (B) was set to 1 Å on the light incident surface. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. As Example 3, the average inclination angle expressed by the surface roughness shown in Fig. 14 (A) and the Fourier spectrum shown in Fig. 14 (B) was 15 on the light incident surface. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. The measurement results of the illuminance of Example 2 and Example 3 are shown in Fig. 24 (A). As an example 4, an average tilt angle represented by the surface roughness shown in Fig. 15 (A) and the Fourier spectrum shown in Fig. 15 (B) on the light incident surface was 20. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. As an example 5, an average tilt angle represented by the surface roughness shown in Fig. 16 (A) and the Fourier spectrum shown in Fig. 16 (B) on the light incident surface was 25. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. Further, as an example 6, the average inclination angle represented by the surface roughness shown in Fig. 17 (A) and the Fourier spectrum shown in Fig. 17 (B) was 30 on the light incident surface. Cutting the polished surface of the light guide plate and setting the illuminance. The measurement results of the illuminances of Examples 4 to 6 are shown in Fig. 24 (B). As an example 7, the average tilt angle expressed by the surface roughness of the surface shown in Fig. 18 (A) 52 201248270 4ZUUpit' and the Fourier spectrum shown in Fig. 18 (B) was used as the light incident surface. 35. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. As an example 8, the average inclination angle expressed by the surface roughness shown in Fig. 19 (A) and the Fourier spectrum shown in Fig. 19 (B) was 40 on the light incident surface. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. Further, as an example 9, the average inclination angle represented by the surface roughness shown in Fig. 20 (A) and the Fourier spectrum shown in Fig. 20 (B) was 45 on the light incident surface. The light guide plate of the polished surface is cut and the illuminance is measured. The measurement results of the illuminances of Examples 7 to 9 are shown in Fig. 24 (C). As an example 10, an average tilt angle represented by the surface roughness shown in Fig. 21 (A) and the Fourier spectrum shown in Fig. 21 (B) on the light incident surface was 50. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. As an example 11, the average tilt angle represented by the surface roughness shown in Fig. 22 (A) and the Fourier spectrum shown in Fig. 22 (B) on the light incident surface was 55. The light guide plate on the polished surface is cut, and the illuminance near the light incident portion is measured. Further, as an example 12, an average tilt angle represented by the surface roughness shown in Fig. 23 (A) and the Fourier spectrum shown in Fig. 23 (B) on the light incident surface was 60. The light guide plate of the polished surface is cut and the illuminance is measured. 53 201248270 4201 lpif The measurement results of the illuminances of the examples l〇 to 12 are shown in Fig. 24(d). Fig. 24 (A) to Fig. 24 (D) are graphs showing the results of measurement of the degree of knowledge in the vicinity of the light incident portion of the examples 1 to 12. Further, the measurement result of the illuminance when the surface of the light incident surface is a mirror surface is also shown as a comparative example. Here, the example 1 is shown by a broken line in Fig. 24(A), the example 2' is indicated by a dotted line, and the example 3 is indicated by a two-dot chain line, and the comparative example is indicated by a solid line. Further, in Fig. 24(B), Example 4 is indicated by a broken line, Example 5 is indicated by a dotted line, Example 6 is indicated by a two-dot chain line, and a comparative example is indicated by a solid line. Further, in Fig. 24(C), Example 7 is indicated by a broken line, Example 8 is indicated by a dotted line, Example 9 is indicated by a two-dot chain line, and a comparative example is indicated by a solid line. Further, in Fig. 24(D), the example 1 is indicated by a broken line, the example 11 is indicated by a dotted line, the example 12 is indicated by a two-dot chain line, and the comparative example is indicated by a solid line. Further, in order to evaluate the illuminance unevenness, (Lmax - Lmin ) / (Lmax + Lmin ) (visibility) is calculated using the measured maximum value Lmax of the illuminance and the minimum value Lmin '. The relationship between the calculated visibility and the average tilt angle is shown in Fig. 25. The lower the visibility, the smaller the relative difference between the maximum value Lmax of the illuminance and the minimum value Lmin, and the smaller the illuminance unevenness. Further, based on the measured illuminance, the relative light utilization efficiency was obtained based on the light use efficiency of the comparative example (average tilt angle 〇). The light utilization efficiency obtained is shown in Fig. 26. As shown in FIG. 25, in the direction perpendicular to the light incident surface, in the two-layer light guide plate in which the thickness of each of the Jth layer and the second layer is changed, a cut surface is formed on the light incident surface. The light guide plate phase with the light incident surface is a mirror surface. The ratio of the average tilt angle of the polished surface of the light-incident surface is set to 10:2. By 'cutting' reduces the illuminance unevenness near the light incident surface. The relationship between the average tilt angle and the root mean square slope is shown in Fig. 27 below 60. According to the closing table shown in Fig. 27, the average tilt (four) is 1Q. The ~6 range' rms slope is 0.25~4.5. Therefore, the ratio is set to a range of 〇·25 to 4.5, and it is preferable to appropriately reduce the light incident surface = illuminance unevenness. Further, in this range, the shape of the Fourier spectrum of the surface roughness (Fig. 12 (Β) to Fig. 23 (Β)) is the same shape, and the difference is the spatial frequency of the surface shape. Further, in such a range, as shown in FIG. 26, even when the cut surface is formed on the light incident surface, the efficiency is reduced by about several % as compared with the case where the light human face is a mirror surface. Roughly the same. In the above, the light guide plate, the planar (four) device, and the method of manufacturing the light guide plate of the present invention have been described in detail. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Or change. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic perspective view showing an embodiment of a liquid crystal display device including a planar illumination device using a light guide plate according to the present invention. Fig. 2 is a cross-sectional view taken along line π_π of the liquid crystal display device shown in Fig. 1; Fig. 3(A) is a diagram showing the ni_m line of the planar illumination device shown in Fig. 2, and Fig. 3 (Β) is a cross-sectional view taken along line Β-Β of Fig. 3 (Α). 55 201248270 42Ullpif FIG. 4(A) is a perspective view showing a schematic configuration of a light source unit of the planar illumination device shown in FIGS. 1 and 2, and FIG. 4(B) is a view of the light source unit shown in FIG. 4(A). A schematic perspective view of an enlarged LED. Fig. 5 is a schematic perspective view showing the shape of the light guide plate shown in Fig. 3; Fig. 6 is a partially enlarged cross-sectional view showing the light guide plate shown in Fig. 3; Fig. 7 (A) and Fig. 7 (B) are schematic diagrams showing a part of the planar illumination device shown in Fig. 3 in an enlarged manner. 8(A) to 8(E) are schematic cross-sectional views showing another example of the light guide plate of the present invention. Fig. 9A is a schematic cross-sectional view showing another example of the light guide plate of the present invention. Fig. 10 (A) to Fig. 1 (f) are schematic cross-sectional views showing a planar illumination device using another example of the light guide plate of the present invention. Fig. 11A is a schematic cross-sectional view showing a planar illumination device using another example of the light guide plate of the present invention. FIG. 12(A) is a view showing a result of measuring the surface roughness of the cutting and polishing surface formed on the light guide plate of the planar illumination device shown in FIG. 6 in a direction parallel to the longitudinal direction of the light incident surface. Fig. 12 (B) is a diagram showing the conversion of Fig. 12 (A) into a Fourier spectrum. Fig. 13 (A) is a view showing a result of measuring the surface roughness of the cutting and polishing surface of the light guide plate for measurement, and Fig. 13 (B) is a diagram showing the conversion of Fig. 13 (A) into a Fourier spectrum. . Fig. 14 (A) is a view showing a result of measuring the surface roughness of the cutting and polishing surface of the light guide plate used for measurement, and Fig. 14 (B) is a view showing the conversion of Fig. 14 (A) into a Fourier spectrum. . 56 201248270 42011 pif FIG. 15(A) is a view showing the result of measuring the surface roughness of the cutting and polishing surface of the light guide plate used for measurement, and FIG. 15(B) is a diagram showing the conversion of FIG. 15 (A) to the Fourier spectrum. Figure. Fig. 16 (A) is a view showing the results of measuring the surface roughness of the cut and polished surface of the light guide plate used for measurement, and Fig. 16 (B) is a view showing the conversion of Fig. 16 (A) into a Fourier spectrum. Fig. 17 (A) is a view showing the results of measuring the surface roughness of the cut and polished surface of the light guide plate used for measurement, and Fig. 17 (B) is a view showing the conversion of Fig. 17 (A) into a Fourier spectrum. Fig. 18 (A) is a view showing the results of measuring the surface roughness of the cut surface of the light guide plate used for measurement, and Fig. 18 (B) is a view showing the conversion of Fig. 18 (A) into a Fourier spectrum. Fig. 19 (A) is a view showing the results of measuring the surface roughness of the cutting and polishing surface of the light guide plate used for measurement, and Fig. 19 (B) is a view showing the conversion of Fig. 19 (A) into a Fourier spectrum. Fig. 20 (A) is a view showing the results of measuring the surface roughness of the cut and polished surface of the light guide plate used for measurement, and Fig. 20 (B) is a view showing the conversion of Fig. 20 (A) into a Fourier spectrum. Fig. 21 (A) is a view showing the results of measuring the surface roughness of the cut and polished surface of the light guide plate used for measurement, and Fig. 21 (B) is a view showing the conversion of Fig. 21 (A) into a Fourier spectrum. Fig. 22 (A) is a view showing the results of measuring the surface roughness of the cutting and polishing surface of the light guide plate used for measurement, and Fig. 22 (B) is a view showing the conversion of Fig. 22 (A) into a Fourier spectrum. 57 201248270 HZUl 1 pif Fig. 23 (A) is a view showing the result of measuring the surface (four) k-degree row of the cutting and polishing surface of the light guide plate used for measurement, and Fig. 23 (8) is a graph showing the conversion of the map μ (A) into a Fourier spectrum. Figure. Fig. 24) Fig. 24 (D) is a graph showing the measured illuminance. Figure 25 is a table showing the relationship between the average tilt angle and visibility. Fig. 26 is a graph showing the utilization efficiency of light. Fig. 27 is a graph showing the relationship between the average tilt angle and the root mean square slope. 28(A) is a spectrum distribution diagram of an example of a lenticular lens, and FIG. 28(B) is a spectrum distribution diagram of another example of a lenticular lens. Fig. 29 (A) is a spectrum distribution diagram of an example of 稜鏡, and Fig. 29 (b) is a spectrum distribution diagram of another example of 稜鏡. Fig. 30 (A) is a spectrum distribution diagram of an example of a rectangular groove structure, and Fig. 30 (B) is a spectrum distribution diagram of another example of a rectangular groove structure. [Description of main component symbols] 10: Liquid crystal display device 12: Liquid crystal display panel 14: Driving units 20, 156, 166, 176, 186, 196, 206, 226: Backlight unit (planar illumination device) 24: Illumination device body 24a 30a: light exit surface 26: frame 28: light source unit 30, 100, 110, 120, 130, 140, 150, 160, 170, 180, 58 201248270 4201 lpif 190, 200, 210, 220: light guide plate 30b: back 30c: first light incident surface 30d: second light incident surface 32: optical member unit 32a, 32c: diffusion sheet 32b: prism sheet 34: reflection plate 36: upper guide reflection plate 38: lower guide reflection plate 42: lower portion Frame 44: upper housing 44a: opening 46: folding member 48'·support member 49: power supply housing 50: LED chip 52: light source supporting portion 58: light emitting surfaces 60, 102, 112, 122, 132, 142, 152, 162, 172, 182 192, 202, 212, 222: first layer 62, 104, 114, 124, 134, 144, 154, 164, 174, 184 194, 204, 214, 224: layer 2 66: Cutting and grinding surface 59 201248270f

1 IplI 150d :側面 a、b :長度 E :有效晝面區 Μ :混合區 α:二等分線 ζ :邊界面1 IplI 150d : side a, b : length E : effective kneading area Μ : mixing area α: bisector ζ : boundary surface

Claims (1)

201248270 4201 lpif 七、申請專利範圍： 1· 一種導光板，其包括： 矩形狀的光射出面； 至少1個光射入面，設置於上述光射出面的端邊側、 且射入在與上述光射出面大致平行的方向上前進的光； 背面，與上述光射出面為相反側；以及 分散於内部的散射粒子， 具有在大致垂直於上述光射出面的方向上重疊、且上 述散射粒子的粒子濃度不同的2層以上的層， 上述2層以上的層的在大致垂直於上述光射出面的方 向上的厚度各自變化，合成粒子濃度以在垂直於上述光射 入面的方向上，具有上述光射入面側的第丨極大值、及位 於比上述第1極大值更遠離上述光射入面的位置且大於上 述第1極大值的第2極大值的方式變化，且 上述光射入面為在與上述光射入面的長邊方向平行的 方向上’形成有具有規定的週期構造的切削研磨面的粗面。 2. 如申請專利範圍第丨項所述之導光板，其中上述2 層以上的層包含上述光射出面側的第丨層、以及上述散射 粒子的粒子濃度高於上述第丨層的上述背面側的第 2層這 2層，且在垂直於上述光射入面的方向上，上述第2層的 厚度以隨著遠離上述光射入面而暫時變厚，於變薄之後再 次變厚的方式連續地變化。 3. —種導光板，其包括： 矩形狀的光射出面； 201248270 42Ullpif 至少1個光射入面，設置於上述光射出面的端邊側、 且射入在與上述光射出面大致平行的方向上前進的光； 背面’與上述光射出面為相反側；以及 分散於内部的散射粒子， 具有在大致垂直於上述光射出面的方向上重疊、且上 述散射粒子的粒子濃度不同的2層以上的層， 上述2層以上的層的在大致垂直於上述光射出面的方 向上的厚度各自變化，合成粒子濃度以在垂直於上述光射 入面的方向上，具有配置於上述光射入面側的極小值、及 位於比上述極小值更遠離上述光射入面的位置的第2極大 值的方式變化，且 上述光射入面為在與上述光射入面的長邊方向平行的 方向上，形成有具有規定的週期構造的切削研磨面的粗面。 4·如申請專利範圍第3項所述之導光板，其中上述2 層以上的層包含上述光射出面側的第1層、及上述散射粒 子的粒子濃度高於上述第1層的上述背面側的第2層這2 層’且在垂直於上述光射入面的方向上，上述第2層的厚 度以隨著遠離上述光射入面而暫時變薄，然後變厚的方式 連續地變化。 5·如申請專利範圍第1項至第4項中任一項所述之導 光板’其中上述光射入面為設置於上述光射出面的相向的 2個端邊側的2個光射入面，且於2個光射入面各自之側 具有上述第1極大值。 6.如申請專利範圍第5項所述之導光板，其中上述第 62 201248270 42Uilpif 2層的厚度於上述光射出面的中央部最厚。 7.如申請專利範圍第丨項至第4項中任— 2板’其中上述光射人面設置於上述光射“的丨個端邊 侧，且具有1個上述第1極大值。 ^ 8.如申請專利範圍第1項至第4項中任—項所述之 3短述光射入面為形成有形成在與其長邊二向正 的短邊方向上的線狀的週期構造的粗面。 ^9·=請專利範圍第1項至第4項中任1所述之導 率A 形成於上述光射人面的切肖彳研磨面的均方根斜 平局υ.25以上、4 5以下。 、10.如申請專利範圍第8項所述之導光板，其中形成 於上述光射入面的切削研磨面的均方根斜率為〇2^ 上、4.5以下。 · U·⑹巾請專利範圍第1項至第4項巾任-項所述之 一板，其中上述散射粒子為混合有粒徑不同的粒子的 分散粒子。 12.如申請專利範圍第1項至第4項中任一項所述之 一反/、中上述背面為平行於上述光射出面的平面。 工13〕一種導光板的製造方法，其是如申請專利範圍第 1項至第4項巾任—項所述之導光板的製造方法，其包括： 使包括上述散射粒子的粒子濃度不同的2層以上的 a、、上述光射出面、及未形成上述粗面的光射入面的導光 板成形後， 利用機械加工於未形成上述粗面的光射入面上形成上 63 201248270 42Ullpif 述切削研磨面。 Μ·如申V月專利範圍帛i3項所述之導光才反的製造方 法，其中上述機械加工為細線加工。 15. 如申叫專利範圍第14項所述之導光板的製造方 法，其中上述機械加工為如下的加工：於銑床、Nc鉋刮 機、或刨機中，控制其刃具的移動速度及旋轉速度並控 制上述導光板的未形成上述粗面的光射入面與上述刃具的 接觸週期，湘上勒具於未形成上述粗面的光射入面上 形成上述切削研磨面。 16. —種面狀照明裝置，其包括： 如申凊專利範圍第1項至第4項中任一項所述之導光 板；以及 與該導光板的上述光射入面相向'且沿其長邊方向配 置的光源單元。 17·如申請專利範圍第16項所述之面狀照明裝置，其 中上述光源單元包括： 與上述光射入面相向、且於上述光射入面的長邊方向 上等間隔地侧的點光源；以及謂上述點光源的支擒構 件。 18.如申請專利範圍第17項所述之面狀照明裝置其 中將上述點光源的於排列方向上的長度設為2 mm〜4 mm，將形成於上述光射入面的切削研磨面的週期構造的 週期5又為5 μπι〜〇.4 mm 〇 64201248270 4201 lpif VII. Patent application scope: 1. A light guide plate comprising: a rectangular light exit surface; at least one light incident surface disposed on an end side of the light exit surface, and incident on the above Light that travels in a direction in which the light exit surface is substantially parallel; a back surface that is opposite to the light exit surface; and scattering particles that are dispersed inside have overlapping particles that are substantially perpendicular to the light exit surface and that are scattered particles Two or more layers having different particle concentrations, wherein the thickness of the two or more layers in a direction substantially perpendicular to the light exit surface changes, and the synthesized particle concentration has a direction perpendicular to the light incident surface. a first maximum value of the light incident surface side and a second maximum value that is located farther from the light incident surface than the first maximum value and larger than the first maximum value, and the light is incident The surface is a rough surface in which a cutting surface having a predetermined periodic structure is formed in a direction parallel to the longitudinal direction of the light incident surface. 2. The light guide plate according to claim 2, wherein the two or more layers include the second layer on the light exit surface side, and the particle concentration of the scattering particles is higher than the back side of the second layer The second layer of the second layer is in a direction perpendicular to the light incident surface, and the thickness of the second layer is temporarily thickened as it goes away from the light incident surface, and is thickened again after thinning. Change continuously. 3. A light guide plate comprising: a rectangular light exit surface; 201248270 42Ullpif at least one light incident surface disposed on an end side of the light exit surface and incident on a light parallel to the light exit surface Light that advances in the direction; the back surface 'opposite to the light exit surface; and the scattering particles dispersed inside have two layers that overlap in a direction substantially perpendicular to the light exit surface and have different particle concentrations of the scattering particles In the above layer, the thickness of the two or more layers in a direction substantially perpendicular to the light exit surface changes, and the composite particle concentration is disposed in the light incident direction in a direction perpendicular to the light incident surface. a minimum value on the surface side and a second maximum value located at a position farther from the light incident surface than the minimum value, and the light incident surface is parallel to the longitudinal direction of the light incident surface In the direction, a rough surface of the cutting and polishing surface having a predetermined periodic structure is formed. The light guide plate according to claim 3, wherein the two or more layers include the first layer on the light exit surface side and the particle concentration of the scattering particles is higher than the back surface side of the first layer The second layer of the second layer is in a direction perpendicular to the light incident surface, and the thickness of the second layer is continuously changed so as to become thinner as it goes away from the light incident surface, and then becomes thicker. The light guide plate according to any one of the first to fourth aspects of the invention, wherein the light incident surface is two light incidents provided on two opposite end sides of the light exit surface. The surface has the first maximum value on each side of the two light incident surfaces. 6. The light guide plate according to claim 5, wherein the thickness of the 62nd 201248270 42Uilpif 2 layer is the thickest at a central portion of the light exit surface. 7. In the second to fourth aspects of the application of the patent scope - 2, wherein the light-emitting surface is disposed on the side of the light-emitting side, and has one of the first maximum values. ^ 8 The short-term light incident surface described in any one of the first to fourth aspects of the patent application is formed by a thick periodic structure formed in a short side direction which is formed in a direction perpendicular to the long side of the long side thereof. ^9·=Please refer to the conductivity A described in any one of the first to fourth aspects of the patent range. The root mean square slope of the cut surface of the above-mentioned light-emitting surface is 25.25 or more, 4 The light guide plate according to claim 8, wherein the root mean square slope of the cutting and polishing surface formed on the light incident surface is 〇2^, and 4.5 or less. · U·(6) towel The above-mentioned scattering particles are dispersed particles in which particles having different particle diameters are mixed, as in the first to fourth items of the patent scope, in the first to fourth items of the patent application. In any one of the above, the back surface is a plane parallel to the light exit surface. [13] A method of manufacturing a light guide plate, which is The method for producing a light guide plate according to any one of claims 1 to 4, further comprising: a layer of two or more different in particle concentration including the scattering particles, the light exiting surface, and After the light guide plate on which the light incident surface of the rough surface is not formed is formed, the cutting surface is formed by machining on the light incident surface on which the rough surface is not formed. Μ·如申V月专利范围帛The manufacturing method of the light guide according to the item i3, wherein the machining is a thin wire processing. The manufacturing method of the light guide plate according to claim 14, wherein the machining is as follows: In the milling machine, the Nc planer, or the planer, controlling the moving speed and the rotating speed of the cutting tool and controlling the contact period of the light incident surface of the light guide plate not forming the rough surface with the cutting tool, The surface of the light incident surface on which the rough surface is formed is formed by the above-mentioned cutting and polishing surface. 16. A planar illumination device comprising: the light guide according to any one of claims 1 to 4 And a light source unit of the light guide unit of the light guide plate of the light guide plate, wherein the light source unit is disposed in the longitudinal direction of the light guide plate, wherein the light source unit comprises: a point light source in which the light incident surfaces face each other at equal intervals in the longitudinal direction of the light incident surface; and a support member of the point light source. 18. The surface according to claim 17 In the illuminating device, the length of the point light source in the arrangement direction is set to 2 mm to 4 mm, and the period 5 of the periodic structure of the cutting and polishing surface formed on the light incident surface is 5 μπι to 〇.4 mm. 〇64
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